Classification of elements

1 mark questions

1. What do you mean by periodicity in periodic table?
Ans: Periodicity of a periodic table is the recurrence or repeating trends in the properties of elements when they are arranged on the basis of certain law. 
2. State Mendeleev's periodic law.
Ans: Mendeleev's periodic law states that the physical and chemical properties of the element are periodic function of their atomic weights.
3. What is the basis of Mendeleev’s periodic law?
Ans: Atomic weight the element is the basis of Mendeleev's periodic law.
4. State modern periodic law (Moosely periodic law).
Ans: Modern periodic table states that the physical and chemical properties of elements are the periodic functions of their atomic numbers.
5. What is the basis of classification of elements in Mendeleev’s periodic table?
Ans: In Mendeleev's periodic table, elements were arranged on the basis of the fundamental property, atomic mass, and chemical properties. 
6. What are the vertical columns and horizontal row of the modern periodic table?
Ans: In moder periodic table the vertical columns are called groups and the horizontal rows are called periods.
7. How many periods and groups are there in a modern periodic table?
Ans: In the modern periodic table, there are 7 periods and 18 groups.
8. What is valency?
Ans: The combining capacity of element is called valency.
9. What is transition elements?
Ans: The B group element (d block) which lie in between IIA and IIIA group elements are called transition elements. 
or, 
The transition elements are those elements having a partially filled d or f subshell in any common oxidation state.
10. What are inner transition elements?
Ans: Lanthanides and actinides (f block) are called inner-transition elements. 
11. What is the position of lanthanides in the Modern periodic table?
Ans: The position of lanthanides in the Modern periodic table is in sixth period starting from atomic number 51 to 71. 
12. What is the valency of elements in group 5 of the modern periodic table?
Ans: The valency of elements in group 5 of the modern periodic table is 3 because it needs 3 electrons to complete it octet in outer most orbit.
13. How many electrons do s, p, d, f sub shell of periodic table can accommodate?
Ans: The maximum number of electrons that s orbital can accommodate is 2, p is 6, d is 10 and f is 14. 
14. On what basis the elements of modern periodic table are classified into s, p, d, f block?
Ans: The elements of modern periodic table are classified into s, p, d, f block on the basis of the entry of the outer most electron of an element into an orbital.
15. Name some inert elements.
Ans: Some inert elements are argon, neon, helium, xenon etc. 
16. How many blocks are there in the modern periodic table?
Ans: There are 4 blocks in the modern periodic table. 
17. Which one is more reactive between Fluorine and Chlorine? Why?
Ans: Fluorine is more reactive than chlorine because fluorine is more electronegative than chlorine.
18. Mention the group numbers of noble gases, most reactive non-metals and most
      reactive metals.
Ans: Noble gases are in the group 18, most reactive non-metals are in group 17 and most reactive metals are in group 1. 
19. What is electropositivity?
Ans: Electopositivity can be defined as the tendency of atom to donate elections and form positively charged cations.
20. Define ionization energy.
Ans: Ionization energy is the minimum amount of energy required to remove the most loosely bound electron of an atom or molecules.
21. What is electronegativity?
Ans: Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the valance electrons from other atoms.
22. Define atomic radius.
Ans: Atomic radius is the distance from the centre of the nucleus to the outermost shell containing electrons.
23. What is valance electron?
Ans: The electrons at the outer most shells that determines the properties of an element is called valance electron. 
24. What is electronic configuration?
Ans: The distribution of electrons in different orbits is known as electronic configuration.
25. What are inert gases?
Ans: Inert gas is a gas that does not undergo chemical reactions under a set of given condition.
26. Write down the names of noble metals.
Ans: The name of the noble metals are: rhenium, ruthenium, rhodium, palladium, silver, osmium, platinum, iridium and gold.
27. What is the valency of zero group element?
Ans: The valency of zero group element is zero. 
28. How many periods and groups are there in Mendeleev's periodic table?
Ans: There are 8 groups and 7 periods in Mendeleev's periodic table .
29. Name the group number of alkali metals, alkali earth metals, halogens and noble gases.
Ans: The group number of alkali metals is 1st , alkali earth metals are in 2nd group, halogens are in 17th group and noble metal are in 18th group.
30. What is the formula to find the maximum number of electrons in any orbit?
Ans: The formula to find the maximum no. of any orbit is 2n2(square) where n is the no. of orbit.
31. Give the name of any two metalloids except silicon.
Ans: Any two metalloids except silicon are Germanium and Boron.
32. What is the usual difference between the electronic configuration of a metal and
      non-metal?
Ans: Metals are considered to be electropositive in nature due to their ability to donate electrons whereas non-metals are electronegative as they generally accept electrons.
33. What does the terms duplet and octet mean?
Ans: Octet is an atom or an ion having a maximum of eight electrons in the outermost shell .
Duplet is an atom having the maximum of two electrons in the outermost shell.
34. Write the shape of p & d sub shell?
Ans: Shape of p orbital is dumbbell shaped and d orbital is cloverleaf shaped or double dumbell shaped.
35. Write the two factors that determine the reactivity of elements?
Ans: The two factors that determine the reactivity of elements are: valance electrons and atomic radius.
36. Write the name and group of the element whose electronic configuration is
      1s2, 2s22p6, 3s23p6,4s1.
Ans: The name of the element with given electronic configuration  is potassium (K) and its group is 1 (alkali metal). 
37. What is orbital?
Ans: The region or space around the nucleus of an atom where the probability of finding an electron is maximum is called orbital. There are six orbitals. They are s, p, d, and f. 
38. What is Halogen?
Ans: A halogen is a chemical element that forms a salt when it reacts what with metal. 
39. What are metalloids?
Ans: An element whose properties are intermediate between those of metals and non-metals or semiconductors are called metalloids

2 marks questions

1. What is periodic table?
Ans: A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure appear in vertical columns is called periodic table.
2. Write the advantages of periodic table.
Ans: the advantage of periodic table are: 
1. The classification of elements is based on the atomic number, which is a more fundamental property.
2. The reason for placing isotopes at one place is justified as the classification is on the basis of atomic number.
3. Define groups and periods.
Ans: The vertical column of periodic table is called group. The horizontal row of periodic table is called period
4. Why did Mendeleev leave many gaps in his periodic table?
Ans: Mandeleev left many gaps in his periodic table because he predicted that there would be such elements which will fill in the gaps in future. He also predicted the properties of these element.
5. How are the periodic table and valency related? Explain with examples.
Ans: The valency of elements goes on increasing from 1 to 5 from left side (from metals) of the periodic up to the middle and decreases from 4 to 0 when we move further right (to non-metals) to the periodic table. 
6. Why is IA group of Modern periodic table called alkali metals?
Ans: IA group of modern periodic table is called alkali metals because their hydroxide are highly soluble in water.
7. Why is VIIA group of Modern periodic table called halogen?
Ans: VIIA group of Modern periodic table called halogen because they react with metal to produce salt. 
8. Why is IIA group of Modern periodic table called alkali earth metals?
Ans: Group IIA of modern periodic table called alkali earth metals because they form alkaline solutions when they react with water.
9. Why VIIIA group of Modern periodic table are called inert elements?
Ans: Group VIII A of modern periodic table are called inert element because they do not react with any other elements as the outer most shell of the elements are fulfilled. So, they do not gain or loose electrons.  
10. Why is the classification of elements considered as the important achievement
      in the study of chemistry?
Ans: Classification of elements is considered as the importance achievement in the study of chemistry because it makes the study of elements easy, scientific and practicable.
11. Mention the special features of modern periodic table.
Ans: Feature of modern periodic table are:
1)Elements are arranged in the increasing order of atomic numbers.
2)Elements are placed in periods base on the no. of shell in their atoms.
12. What are Lanthanides and Actinides?
Ans: The elements with atomic number 57 to 71 are called lanthanides.
The elements with atomic number 89 to 103 are called actinides.
13. How are elements arranged in the periodic table according to electronic configuration?
Ans: The electronic configuration of an element is related to its position on the periodic table . The no. of electrons in the outermost shell of an element is represented in the periodic table as the group no. that element is situated in and the number of shell in the electronic configuration represents the period in the periodic table. 
14. Why hydrogen is placed both in first and seventh group in the periodic table?
Ans: hydrogen is placed both in first and seventh group in the periodic table because it shows the properties which are similar to the alkali metals i.e IA group and also shows the properties which are similar to the halogens .i.e VIIA group.
15. Give two reasons for placing hydrogen with halogen.
Ans: two reasons for placing hydrogen with halogen are
a. Like halogen, hydrogen has one electron less then the nearest noble gas.
b. Hydrogen gain one electron to stabilize itself as halogen. 
16. How do the metallic characteristics change in a period from left to right in the
      periodic table?
Ans: When we observe elements from left side of periodic table metallic character reduces up to the middle of table and metalloids are seen. Non-metals can be seen to the right side the periodic table when we observe beyond metalloids. 
17. How does atomic radius changes from left to right in a period and top to
      bottom down a group?
Ans: Atomic radius decreases from left to right in a period of the periodic table due to increase in nuclear charge atomic radius decreases steadily from left to right and the radius of atom increases from top to bottom down a group 
18. Write down the two difference between metal and non-metal.
Ans: 
19. State one region for placing chlorine and bromine in the same group in the periodic table.
Ans: One reason for placing chlorine and bromine in the same group in the periodic table is:
They both are non metal and also forms salt.
20. Why potassium is more reactive than lithium?
Ans: Potassium is more reactive than lithium because potassium has a more loosely bound valence electron, so the outermost election can be easily removed with few energy. In direct reactions, potassium react more violently than lithium.
21. Why are elements belonging to zero group inactive?
Ans: Elements belonging to zero group are inactive because their outermost shells are completely filled with electrons. So that they have little tendency to gain or lose electrons.
22. Why fluorine is more reactive than chlorine?
Ans: When we move form top to bottom in a group on non-metals, the atomic size increases gradually. So, the nuclear attraction for electrons of the other atom decreases. As a result, the tendency of non-metallic atom to gain election decreases. Therefore, the reactivity of non-metals at top i.e fluorine is more than chlorine.
23. Define Isotopes and Isobar.
Ans: Isotopes is the atoms of same elements having the same numbers of proton but different number of neutrons. Eg.  protium (A = 1), deuterium (A = 2), and tritium (A = 3)
Isobar is the atoms of different elements having the same atomic mass. Eg.  S (A=40), Cl(A=40), Ar(A=40), K(A=40) and Ca(A=40).
24. Write two differences between the Mendeleev's periodic table and the
      modern periodic table.
Ans: The differences between Mendeleev's and modern periodic table are: 

S.no

Mendeleev’s periodic table

Modern Periodic table

1

Elements are classified on the basic of increasing atomic weight.

Elements are classified on the basic of increasing atomic numbers.

2

There are eight vertical columns which are the groups of this periodic table.

There are eighteen vertical columns which are group of this periodic table
25. Write any two differences between s and p block elements.
Ans: The differences between S and P block elements are: 

S.no

S-block elements

P-block elements

1

The elements in which the last electron enter s-subshell are called s-block elements.

The elements in which the last electron enters p-subshell are called p-block elements.

2

They are placed in the left side of periodic table.

They are placed in the right side of periodic table .
26. Why does the chemical reactivity of elements increase on moving from top to
      bottom in group 1 of modern periodic table?
Ans: Chemical reactivity of elements increases on moving from top to bottom in group 1 of modern periodic table because the atomic radius or size increases gradually. Due to which nuclear force of attraction to the valance electron decreases. As a result, the tendency of metal to lose electron increases.
27. Elements of group 15, 16 and 17 are less reactive as we go down in the
      group of the modern periodic table, why?
Ans: Elements of group 15, 16 and 17 are less reactive as we go down in the group of the modern periodic table because the atomic size of elements increases as we move downwards in groups. The elements of group 15, 16 and 17 are non metal, the chemical reactivity of non-metals decreases when atomic size of those elements increases.
28. Write any two reasons that hydrogen is kept in group 1 in Modern periodic table.
Ans: Two reasons why hydrogen is kept in group 1 in Modern periodic table are:
1. like other alkali metals, it can lose its 1 electron to stabilize itself.
2. It react with oxygen to form the oxide like other alkali metals.
29. Write down the electronic configuration of given elements on the basis of sub shells.
       (I) (Oxygen) (iii) (Chlorine)
Ans: The electronic configuration of given elements are: 
i. Oxygen: 1s2, 2s2 2p4
ii. Chlorine: 1s2, 2s2 2p6, 3s2 3p5 
30. Give two appropriate reasons for why Na is called alkali metal and Si is called metalloids.
Ans: i. Na is called alkali metal because it produces alkali when it react with water, whereas Si resembles with  both metal and non-metal.
ii. Na has 1 valance electron, so it can easily loose that electron but silicon has four electrons in its outer most orbit which it can donate like a metal or it can also accept four electrons like a non-metal. So, it shows both the properties of metals and non-metals. So, it is called metalloid or semi conductor. 
31. Why elements of group VIIIA are called noble gases?
Ans: The elements of group VIIIA or 18 are called noble gases because its octet (or duplet) is complete i.e its outer most shell contains 8 (or 2) electrons which is stable configuration. So, it neither donates nor gain electrons and all the elements this group are gases. 
32. Why are the elements Be, Mg and Ca are placed in the same group in modern periodic table?
Ans: Be, Mg and Ca re placed in the same group in the modern periodic table because all of them have the same electronic configuration containing two electrons in the valance shell and the oxides of these elements are similar to those of alkali metals.
33. Write down two defects in the Mendeleev's periodic table.
Ans: Any two defect of Mendeleev's periodic table are:
1. Unable to locate hydrogen in the periodic table.
2. Position of isotopes were not fixed. 
34. Inert gases are kept in zero group, why?
Ans: The elements of group VIIIA or 18 are called noble gases because its octet (or duplet) is complete i.e its outer most shell contains 8 (or 2) electrons which is stable configuration. They neither donates nor gains electrons, so they are kept in zero group. 
35. Atomic size of inert gases do not affect inertness, why?
Ans: The reactivity of an element depend up on the number of electrons shared, gained or lost. In case of inert gases each of them has a full outer shell of electrons, due to which they are do not share, gain or lose electrons from valance shell irrespective of atomic size.
36. An element A has atomic number 29. Point out it’s position in Modern periodic table.
Ans: The element A is cupper which lies is the middle of the fourth period of the periodic table falling in d-block. It is in the block of metal. It is in the IB (or 11) group of periodic table. 
37. Which are very short, short, long and very long periods in the modern periodic table?

38. Elements group VA, VIA and VIIA are less reactive as we go down in these groups of the
      modern periodic table, why?

39. Why the reactivity of meals increases with the increase in the radius of atoms? 

40. What is the reactivity of an element?
Ans: Reactivity of an element is the tendency of an element to combine with another element by gaining or loosing or sharing electrons from the outer most shell. 

3 marks questions
41. Why does atomic size decrease down a group?

42. Which one is more reactive Na or K? Give reason.

43. Electronic configuration of two elements are given below:
      X: 1s2, 2s2 2p6, 3s1
      Y: 1s2, 2s2 2p6, 3s2 3p5

     i. Which one would you suggest is larger?
    ii. Write the name of the elements and show the electronic configuration.

44. Study the table and answer the following questions on the basis of the following table:
Elements
Electronic configuration
 X
1s2,2s2 2p6, 3s1
 Y
1s2,2s2 2p6, 3s2 3p5
 Z
1s2,2s2 2p6, 3s2 3p6

i. Write the name of elements X and Y.

ii. Write the blocks of the elements X and C.

iii. Write the name of element indicated by Z and its valency.

45. Write down any three characteristic s of the modern periodic table which are not present in       
      Mendeleev’s periodic table.

46. Define proterium, deuterium and tritium.

47. Write the electronic configuration of an element that fall in second period and in group VIA? 
      Also indicate its block.

4 marks questions

48. Hydrogen is kept with metals although it is being a non-metal, why?

49. Study the table and answer the following questions:
Li
Be
B
C
N
O
F
Na
Na
Mg
Al
Si
P
S
Cl
Ar

     i. Write down the chemical compound which is formed by combining Na and Cl
    ii. How are these elements arranged?
   iii. Generally, in which group of periodic table the metalloids are kept?
   iv. Which one more reactive between Li and Na and why?

50. What happens to metallic property of elements on moving left to right of a period of a periodic
      table? Between chlorine and fluorine which one is more reactive and why?

51. Study the table and answer the following questions on the basis of the following table:

 Elements
Electronic configuration
 A
1s2,2s2 2p6, 3s1
 B
1s2,2s2 2p6, 3s2 3p5
 C
1s2,2s2 2p1

    i. Between A and C which one is more reactive and why?
   ii. Write the balanced chemical equation between A and C.
   iii. What type of chemical reaction is it?
   iv. In which block does element B lie and why?

52. Study the given portion of the periodic table and answer the questions:
He
Ne
Ar
Xe
Rn
     i. On moving down this group, what change can be seen in the reactivity and why?

     ii. On which group do, these elements belongs and why?

     iii. What is this group called and why?

53. Write the capacity of shell and sub-shell to hold maximum number of electrons.

54. Write the demerits of Mendeleev’s periodic table.

55. Write the merits of Modern periodic law.

56. Study the table and answer the following questions on the basis of the following table:
 Elements
Electronic configuration
 A
1s2,2s2 2p6, 3s2
 B
1s2,2s2 2p6, 3s2 3p6
 C
1s2,2s2 2p6 3s2 3p5

    i. Which one is metal?

   ii. Which one is non-metal?

  iii. Which one is inert, why?

  iv. What happens when A and B react?

57. What happens to the reactivity while moving top to bottom in metallic group of modern periodic
      table?

58. What happens to the reactivity while moving top to bottom in non-metallic group of modern
      periodic table?

59. What happens to the reactivity while moving bottom to top in metallic group of modern periodic
      table?

60. What happens to the reactivity while moving bottom to top in non-metallic group of modern
      periodic table?

61. What happens to the reactivity while moving top to bottom in non-metallic group of modern
      periodic table?

62. In which group of the modern periodic table are the very active metals and very active nonmetals
      lies? Clarify the relation between the size of atoms of these metals and nonmetals with their
      chemical reactivity.
63. On what factors does the Modern periodic table is different from that of the
      Mendeleev's periodic table?
Ans: The factors in which modern periodic table is different from that of Mendeleev's periodic table are: 
i. Modern periodic table is based on atomic number but Mendeleev's periodic table is based in atomic mass. 
ii. There were 63 elements in Mendeleev's periodic table but there are 118 elements listed in modern periodic table.
iii. Position of isotopes, lanthanides and actinides, dissimilar elements and position of metals, non-metals and metalloids are fixed in the modern periodic table. 
iv. wrong arrangement of atomic masses of some elements are also fixed. 

300 comments:

  1. Gagan PandeyWed Nov 04, 02:52:00 PM

    2. Mark Qn 1Periodic table is a table of the chemical elements arranged in order of atomic number in a row with similar atomic structure.

    ReplyDelete
  2. Gagan PandeyWed Nov 04, 02:57:00 PM

    The advantage of periodic table are
    1. It's easier to remember the
    properties of element.

    ReplyDelete
  3. sciencewingsblogspot.comWed Nov 04, 08:30:00 PM

    q no. 4 (yash) modern periodic table states that the physical and chemical properties of elements are the periodic functions of their atomic numbers.

    ReplyDelete
  4. sciencewingsblogspot.comWed Nov 04, 08:34:00 PM

    q no, 2 (yash) mendeleev's periodic law states that the physical and chemical properties of the elements are periodic function of their atomic weights.

    ReplyDelete
  5. SalinaThu Nov 05, 11:31:00 AM

    Q NO 1
    periodicity refers to trends or recurring variations in element properties with increasing atomic number.

    ReplyDelete
  6. SalinaThu Nov 05, 11:33:00 AM

    Q NO 2
    Mendeleev's periodic law states that the physical and chemical properties of the element are periodic function of their atomic weights.

    ReplyDelete
  7. SalinaThu Nov 05, 11:46:00 AM

    Q NO 3
    Atomic weight is the basis of mendeleev's periodic law.

    ReplyDelete
  8. SalinaThu Nov 05, 11:58:00 AM

    Q NO 4
    Modern periodic law states that the physical and chemical properties of elements are the periodic functions of their atomic numbers.

    ReplyDelete
  9. Gagan PandeyThu Nov 05, 12:12:00 PM

    1 mark Qno 2
    mendeleev periodic law state that the physical and chemical properties
    of element are the periodic function of their atomic weights .

    ReplyDelete
  10. SalinaThu Nov 05, 12:13:00 PM

    Q NO 5
    In Mendeleev's periodic table, elements were arranged on the basis of the fundamental property, atomic mass, and chemical properties

    ReplyDelete
  11. YuginnThu Nov 05, 12:17:00 PM

    Sonu

    Q.no: 7

    There are 7 periods and 18 groups in a modern periodic table.

    ReplyDelete
  12. UnknownThu Nov 05, 12:19:00 PM

    Shubhekshya

    Q.no.6

    IA group of modern periodic table is called alkali metals because their hydroxide are highly soluble in water.

    ReplyDelete
  13. SalinaThu Nov 05, 12:19:00 PM

    Q NO 6
    In moder periodic table the vertical columns are called groups and the horizontal rows are called periods.

    ReplyDelete
  14. sujanThu Nov 05, 12:21:00 PM

    Q.NO.8 The combining capacity of element is called valency.

    ReplyDelete
  15. SalinaThu Nov 05, 12:21:00 PM

    Q NO 7
    In the modern periodic table, there are 7 periods and 18 groups

    ReplyDelete
  16. Gagan PandeyThu Nov 05, 12:23:00 PM

    1 mark 4Q
    Modern periodic law states that the physical and chemical properties of the elements are the periodic function of their atomic numbers.

    ReplyDelete
  17. UnknownThu Nov 05, 12:23:00 PM

    VIIA group of modern periodic table are called halogens because they form salt with IA elements. For example: NaCl

    ReplyDelete
  18. Srikesh Kc 😈Thu Nov 05, 12:25:00 PM

    9 The transition elements are those elements having a partially filled d or f subshell in any common oxidation state.

    ReplyDelete
  19. SalinaThu Nov 05, 12:25:00 PM

    Q NO 8
    The combining power of an element, is called valency.

    ReplyDelete
  20. sandhyaThu Nov 05, 12:27:00 PM

    Q NO 8 Ans: The combining power of an element especially as measured by the number of hydrogen atoms it can displace or combine with element is called valency.

    ReplyDelete
  21. Srikesh Kc 😈Thu Nov 05, 12:28:00 PM

    10) Lanthanides and actinides are called inner-transition elements

    ReplyDelete
  22. SujanThu Nov 05, 12:28:00 PM

    Q.NO.9 The B group element which lie in between IIA and IIIA group elements are called transition elements.

    ReplyDelete
  23. sciencewingsblogspot.comThu Nov 05, 12:28:00 PM

    q no. 10 (yash) actinides and lanthanides are called inner transition elements.

    ReplyDelete
  24. UnknownThu Nov 05, 12:29:00 PM

    2 mark Q no.12

    Subhekshya

    The elements with atomic number 57 to 71 are called lanthanides.

    The elements with atomic number 89 to 103 are called actinides.

    ReplyDelete
  25. SujanThu Nov 05, 12:30:00 PM

    QNO.10 Those element which lie in between the IIIB and IVB group element are called inner transition element.

    ReplyDelete
  26. Gagan PandeyThu Nov 05, 12:31:00 PM

    1 mark 9Q
    the set of metallic group which occupying a central of( IVB-VIII'IB and IIB or 4-12) in the periodic table is called transition element for eg iron chromium copper etc

    ReplyDelete
  27. Srikesh Kc 😈Thu Nov 05, 12:32:00 PM

    19 Electropositivity is the measure of the ability of elements (mainly metals) to donate electrons to form positive ions. Srikesh

    ReplyDelete
  28. UnknownThu Nov 05, 12:35:00 PM

    2 mark Q.no.8

    Subhekshya

    IIA group of modern periodic table is called alkali earth metals because these metals dissolve less in water to form alkali.

    ReplyDelete
  29. SalinaThu Nov 05, 12:35:00 PM

    Q NO 11
    The position of lanthanides in the Modern periodic table is in sixth period.

    ReplyDelete
  30. YuginnThu Nov 05, 12:35:00 PM

    Q.no .9

    A Transition elements is one which can form one or more stable ions with a partially occupied sub- shells.

    ReplyDelete
  31. Ranjita TamangThu Nov 05, 12:39:00 PM

    1 marks questions no.8
    The combining power of an element,especially as measured by the number of hydrogen atoms it can displace or combine with elements is known as Valency

    ReplyDelete
  32. SalinaThu Nov 05, 12:39:00 PM

    Q NO 12
    the valency of elements in group 5 of the modern periodic table is 3.

    ReplyDelete
  33. SalinaThu Nov 05, 12:41:00 PM

    Q NO 13
    s, p, d, f sub shell of periodic table can accommodate 2 electrons.

    ReplyDelete
  34. sandhyaThu Nov 05, 12:41:00 PM

    2 marks Q
    QNo 19:Electopositivity can be defined as the tendency of atom to donate electons and form postively charged cations.

    ReplyDelete
  35. Srikesh Kc 😈Thu Nov 05, 12:41:00 PM

    21 Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the bonding electrons.

    ReplyDelete
  36. sandhyaThu Nov 05, 12:43:00 PM

    2 marks Q
    Q N0:20 Ionization energy is the minimum amount of energy required to remove the most loosely bound electron of an isolated neutral gaseous atom or molecules.

    ReplyDelete
  37. UnknownThu Nov 05, 12:47:00 PM

    Q.NO.17 Fluorine and chlorine are electronegative elements of Group VIIA. These elements have seven valence electrons so it they have to gain one electron to be stable or to take part in chemical reaction. The atomic size of chlorine is larger than fluorine so nuclear attraction force of chlorine is less than the fluorine. So it is easy to gain one electrons with more nuclear attraction force for fluorine than chlorine therefore fluorine is more reactive than chlorine.

    ReplyDelete
  38. sandhyaThu Nov 05, 01:08:00 PM

    2 marks Q
    Q No 21: Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.

    ReplyDelete
  39. sandhyaThu Nov 05, 01:11:00 PM

    2 marks Q
    Q No:22 The atomic radius of a chemical element is a measure of the size of its atoms,usually the mean or typical distance from the centre of the nucleus to the boundary of the surrounding shells of electrons.

    ReplyDelete
  40. sandhyaThu Nov 05, 01:13:00 PM

    2marks Q
    Q NO:23 Valance electrons is the outermost shell of the atom that determine an atom's or group's ability to bond with others.

    ReplyDelete
  41. sandhyaThu Nov 05, 01:15:00 PM

    2 marks Q
    Q No:24 Electonic configuration is the distribution of electons of an atom or molecules on atomic or molecular orbitals.

    ReplyDelete
  42. sandhyaThu Nov 05, 01:17:00 PM

    2 marks Q
    Q No:25 An inert gas is a gas that does not undergo chemical reactions under a set of given conditions.
    It is also known as nobel gas.

    ReplyDelete
  43. SalinaThu Nov 05, 02:51:00 PM

    Q NO 14
    the elements of modern periodic table are classified into s, p, d, f block on the basis of the entry of the outer most electron of an element into an orbital.

    ReplyDelete
  44. SalinaThu Nov 05, 02:54:00 PM

    Q NO 16
    There are 4 blocks in the modern periodic law.

    ReplyDelete
  45. sciencewingsblogspot.comThu Nov 05, 03:18:00 PM

    Q NO. 14 (YASH) The elements of modern periodic table are classified into s,p,d,f block according to respective electrons filled in the s,p,d,f orbitals in atom of elements.

    ReplyDelete
  46. Gagan PandeyThu Nov 05, 03:19:00 PM

    11 the position of lanthanides in the modern periodic table is in sixth period

    ReplyDelete
  47. Gagan PandeyThu Nov 05, 03:22:00 PM

    12 the valency of elements in group 5 of the modern periodic table 3

    ReplyDelete
  48. Gagan PandeyThu Nov 05, 03:28:00 PM

    13
    Tow accommodate electrons are there in s,p,d,f sub shell of periodic table.

    ReplyDelete
  49. Gagan PandeyThu Nov 05, 03:37:00 PM

    14
    the elements of modern periodic table are classified into s,p,d,f block on the basis of the entry of the outer most electron of element into an orbital.

    ReplyDelete
  50. UnknownThu Nov 05, 03:40:00 PM

    anuka puri
    Q NO 1

    Periodicity refers to trends or recurring properties with increasing atomic number

    ReplyDelete
  51. Gagan PandeyThu Nov 05, 03:45:00 PM

    15
    mendeleev periodic table is based on the properties of element and weight of atomic element but the modern periodic table is based on atomic number , their fundamental property that decides the properties of element

    ReplyDelete
  52. Gagan PandeyThu Nov 05, 03:47:00 PM

    16
    4 blocks are there in the modern periodic law .

    ReplyDelete
  53. UnknownThu Nov 05, 03:48:00 PM

    Anuka puri
    Q no 2
    mendeleevs periodic law states that the physical and chemical properties of the element are periodic function of their atomic weights

    ReplyDelete
  54. UnknownThu Nov 05, 03:50:00 PM

    Anuka puri
    Q no 3
    atomic weight is the basis of mendeleevs periodic law

    ReplyDelete
  55. Gagan PandeyThu Nov 05, 03:55:00 PM

    17
    fluorine is more reactive than the chlorine because fluorine is electronegative

    ReplyDelete
  56. UnknownThu Nov 05, 03:56:00 PM

    Anuka puri
    Q no 4
    modern periodic law states that the physical and chemical properties of elements are the periodic function of their atomic number

    ReplyDelete
  57. UnknownThu Nov 05, 04:09:00 PM

    Anuka puri
    Q no 5
    In mendeleevs periodi tabal,elements were arranged on the basis fun damental property, atomic mass,and chemical properties

    ReplyDelete
  58. UnknownThu Nov 05, 04:13:00 PM

    Anuka puri
    Q no 6
    In modern periodic tabal the ventical colum are called groups and the horizontal rows are called period

    ReplyDelete
  59. UnknownThu Nov 05, 04:17:00 PM

    Anuka puri
    Q no 7
    In themodern periodic table thre are seven period and 18 groups

    ReplyDelete
  60. UnknownThu Nov 05, 04:23:00 PM

    Anuka puri
    Q no 8
    the combining capacity of elements is called valency

    ReplyDelete
  61. UnknownThu Nov 05, 04:28:00 PM

    Anuka puri
    Q no 9
    the B group















    Anuka puri
    Q no 9
    the B group element d block which lie in between are called transition elements

    ReplyDelete
  62. UnknownThu Nov 05, 04:32:00 PM

    ANUKA Puri
    Q no 10
    lanthanides and actinides F block are called inner transition elements

    ReplyDelete
  63. UnknownThu Nov 05, 04:43:00 PM

    Anuka puri
    Q no 11
    the position of lanthanides in the modern periodic table is in sixth period

    ReplyDelete
  64. UnknownThu Nov 05, 04:46:00 PM

    Anuka puri
    Q no 12
    the valency of elements in group 5 of the modern periodic tabie is 3

    ReplyDelete
  65. UnknownThu Nov 05, 04:49:00 PM

    Anuka puri
    Q no 13
    s,p,d,f sub shall of periodic table can accommodate z electeons

    ReplyDelete
  66. UnknownThu Nov 05, 04:55:00 PM

    Anuka puri
    Q no 14
    the elements of modern periodic table are classified into s,p,d,f block on the basis of the entry of the outer most electron of an element into an orbofan

    ReplyDelete
  67. amuna basnetThu Nov 05, 05:13:00 PM

    This comment has been removed by the author.

    ReplyDelete
  68. amuna basnetThu Nov 05, 05:17:00 PM

    Q no 11
    The position of lanthanides in the modern periodic table is at period 6th and group 3rd.

    ReplyDelete
  69. amuna basnetThu Nov 05, 05:30:00 PM

    Q no 13
    S,P,D,F, sub shell of periodic table can accommodate 2 electrons.

    ReplyDelete
  70. amuna basnetThu Nov 05, 05:51:00 PM

    Q no 16
    There are 4 blocks in the modern periodic table .

    ReplyDelete
  71. amuna basnetThu Nov 05, 06:06:00 PM

    This comment has been removed by the author.

    ReplyDelete
  72. amuna basnetThu Nov 05, 06:11:00 PM

    Qno 17
    Fluorine is more reactive than chlorine because fluorine has a higher electronegetvity.

    ReplyDelete
  73. amuna basnetThu Nov 05, 06:24:00 PM

    Q no 19
    The tendency of an atom to donate electrons and withdraw form covalent bonds to form positively charged cations.

    ReplyDelete
  74. Ranjita TamangThu Nov 05, 06:35:00 PM

    Q/no 11
    The position of lanthanides in the modern periodic table is known as sixth period

    ReplyDelete
  75. Ranjita TamangThu Nov 05, 06:39:00 PM

    Q/no 12
    The valency of elements in groups 5 of the modern periodic table 3.

    ReplyDelete
  76. Ranjita TamangThu Nov 05, 06:42:00 PM

    Q/no.13
    S,p,d,f sub shall of periodic table can accommodate z elections.

    ReplyDelete
  77. amuna basnetThu Nov 05, 06:44:00 PM

    Q no 20
    Ionization energy is the energy that an electron in a gaseous atom or iron has to absorb to come out of the influence of the nucleus.

    ReplyDelete
  78. amuna basnetThu Nov 05, 06:47:00 PM

    Q no 21
    Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the bonding electrons.

    ReplyDelete
  79. Ranjita TamangThu Nov 05, 06:49:00 PM

    Q/no 14
    The elements of modern periodic table are classified into s,p,d,f block on the base of the entry of the outer most electron of an element into an orbofan.

    ReplyDelete
  80. Ranjita TamangThu Nov 05, 06:51:00 PM

    Q/no 16
    There are 4 block of in modern periodic table.

    ReplyDelete
  81. amuna basnetThu Nov 05, 06:54:00 PM

    Q no 22
    Atomic radius is the distance from the centre of the nucleus to the outermost shell containing electrons.

    ReplyDelete
  82. Ranjita TamangThu Nov 05, 06:55:00 PM

    Q/no 17
    Fluorine is more reactive than chlorine because fluorine has a higherkin electronegetvity.

    ReplyDelete
  83. Ranjita TamangThu Nov 05, 06:58:00 PM

    Q/no 19
    The tendency of an atmo to donate electrons and withdraw from covalent bonds to form positively charged cations.

    ReplyDelete
  84. amuna basnetThu Nov 05, 06:59:00 PM

    Q no 23
    Valence electron is an outer shell electron that is associated with an atom,and that can participate in the formation of a chemical.

    ReplyDelete
  85. Ranjita TamangThu Nov 05, 07:04:00 PM

    Q/no 20
    Lonization energy is the minimum amount of energy required to remove the most loosely bound electronot of an isolated neutral gaseous atom or molecular .

    ReplyDelete
  86. amuna basnetThu Nov 05, 07:07:00 PM

    Q no 24
    Electronic configuration is the arrangement of electrons in energy level around an atomic nucleus.

    ReplyDelete
  87. Ranjita TamangThu Nov 05, 07:07:00 PM

    Q/no 21
    Electronegativity is a measure of the tendency of an atom to attract a bounding pair of electrons .

    ReplyDelete
  88. amuna basnetThu Nov 05, 07:09:00 PM

    Q no 25
    Inert gas is a gas that does not undergo chemical reactions under a set of given condition.

    ReplyDelete
  89. amuna basnetThu Nov 05, 07:27:00 PM

    This comment has been removed by the author.

    ReplyDelete
  90. amuna basnetThu Nov 05, 07:31:00 PM

    This comment has been removed by the author.

    ReplyDelete
  91. amuna basnetThu Nov 05, 07:34:00 PM

    Q no 28
    There are 8 groups and 7 periods in mendeleev's periodic table .

    ReplyDelete
  92. amuna basnetThu Nov 05, 07:43:00 PM

    Q no 29
    The group no of alkali metals is 1st , alkali earth metals are in 2nd group, halogens are in 17 group and noble metal are in 18 group.

    ReplyDelete
  93. amuna basnetThu Nov 05, 07:49:00 PM

    Q no 30
    The formula to find the maximum no. of
    any orbit is 2n2(square) where n is the no. of orbit.

    ReplyDelete
  94. amuna basnetThu Nov 05, 08:20:00 PM

    Q no 31
    Any two metalloids except silicon are:
    1]Germaniun
    2]Boron

    ReplyDelete
  95. amuna basnetFri Nov 06, 08:04:00 AM

    Q no 33
    Duplet is the tendency of an atom ro acquire an outer most shell of two electron .
    Octer is the tendency of an atom to acquire an outermost shell of eight electron.

    ReplyDelete
  96. Gagan PandeyFri Nov 06, 08:09:00 AM

    18
    the group numbers of noble gases is 18 in (VIIIa) of the periodic table.
    Fluorine is the most reactive nonmetal. francium is the most reactive metal.

    ReplyDelete
  97. amuna basnetFri Nov 06, 08:12:00 AM

    Q no 36
    The name and group of element whose electronic configuration 1s2,2s2,2p6,3s2,3p6,4s1 is(name) potassium and group 1 ( alkali metals).

    ReplyDelete
  98. Gagan PandeyFri Nov 06, 08:14:00 AM

    19
    Electropositivity is the positive charge of atom to donate electrons .

    ReplyDelete
  99. Gagan PandeyFri Nov 06, 08:18:00 AM

    20
    the energy required to remove electron from molecule is known as Ionization energy.

    ReplyDelete
  100. amuna basnetFri Nov 06, 08:18:00 AM

    Q no 37
    An orbit is an regular repeating path that one object in space takes around another one.

    ReplyDelete
  101. amuna basnetFri Nov 06, 08:22:00 AM

    Q no 38
    Any of the elements flourine,chlorine, bromine, iodine and astetine , occupying group VIIA (17)of the periodic table is called halogen

    ReplyDelete
  102. amuna basnetFri Nov 06, 08:25:00 AM

    Q no 39
    An element whose properties are intermediate betn those of metals and solid non metals or semiconductors is called metalloids.

    ReplyDelete
  103. amuna basnetFri Nov 06, 08:34:00 AM

    Q no 26
    The name of the noble metals are:
    rhenium,ruthenium,rhodium,palladium,
    silver,osmium,platinum,iridium,and gold.

    ReplyDelete
  104. dikshya karkiFri Nov 06, 08:42:00 AM

    q.1 no.27(dikshya karki)
    The valency of zero group element is known as nobel group.Nobel group has 0 valency.

    ReplyDelete
  105. dikshya karkiFri Nov 06, 08:53:00 AM

    q.1 no.26(dikshya karki)
    The name of the noble metals are:
    rhenium,ruthenium,rhodium,palladium,
    silver,osmium,platinum,iridium,and gold.

    ReplyDelete
  106. dikshya karkiFri Nov 06, 08:54:00 AM

    q1 no.28
    There are 8 groups and 7 periods in mendeleev's periodic table .

    ReplyDelete
  107. dikshya karkiFri Nov 06, 08:56:00 AM

    q.1 no.29
    The group no of alkali metals is 1st , alkali earth metals are in 2nd group, halogens are in 17 group and noble metal are in 18 group.

    ReplyDelete
  108. SalinaFri Nov 06, 09:30:00 AM

    Q NO 17
    Fluorine is more reactive between fluorine and chlorine because fluorine has a higher electronegativity than chlorine.

    ReplyDelete
  109. SalinaFri Nov 06, 09:38:00 AM

    Q NO 18
    Most reactive non metals : Fluorine
    Most reactive metal : Alkali metals (Group 1)
    Noble gases : Group 18

    ReplyDelete
  110. SalinaFri Nov 06, 09:39:00 AM

    Q NO 19
    Electropositivity can be defined as the tendency of an atom to donate electrons and form positively charged cations.

    ReplyDelete
  111. SalinaFri Nov 06, 09:42:00 AM

    Q NO 20
    Ionization energy can be defined as the amount of energy required to remove an electron from an isolated atom or molecule.

    ReplyDelete
  112. SalinaFri Nov 06, 09:43:00 AM

    Q NO 21
    Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the bonding electrons.

    ReplyDelete
  113. SalinaFri Nov 06, 09:46:00 AM

    Q NO 22
    Atomic radius is the typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons. simply atomic radius is the radius of an atom.

    ReplyDelete
  114. SalinaFri Nov 06, 09:48:00 AM

    Q NO 23
    A valence electron is a negatively charged particle, located in the outermost shell of an atom.

    ReplyDelete
  115. SalinaFri Nov 06, 09:55:00 AM

    Q NO 24
    The distribution of electrons in different orbits is known as electronic configuration.

    ReplyDelete
  116. YuginnFri Nov 06, 09:56:00 AM

    Q.no : 13

    s, p, d, f sub shells of periodic table can accommodate 2 electrons.

    ReplyDelete
  117. SalinaFri Nov 06, 09:58:00 AM

    Q NO 25
    An inert gas is a gas that does not undergo chemical reactions under a set of given conditions.

    ReplyDelete
  118. YuginnFri Nov 06, 09:58:00 AM

    Q.no: 12

    The valency of elements in group 5 of the modern periodic table is 3.

    ReplyDelete
  119. SalinaFri Nov 06, 10:00:00 AM

    Q NO 26
    Halogen.
    Gold.
    Silver.
    Palladium.
    Ruthenium.
    Platinum.
    Rhodium.
    Osmium. Etc.

    ReplyDelete
  120. SalinaFri Nov 06, 10:03:00 AM

    Q NO 27
    The valency of zero group element is called noble gas whose valency is zero.

    ReplyDelete
  121. YuginnFri Nov 06, 10:04:00 AM

    Q.no : 16

    There are four blocks in the modern periodic law.

    ReplyDelete
  122. SalinaFri Nov 06, 10:05:00 AM

    Q NO 28
    In mendeleev's periodic table, there are eight groups and seven periods.

    ReplyDelete
  123. YuginnFri Nov 06, 10:13:00 AM

    Q.no: 20

    Lonization energy can be defined as the amount of energy required to removed an electron from an isolated atom or molecule.

    ReplyDelete
  124. SalinaFri Nov 06, 10:13:00 AM

    Q NO 29
    Alkali metal: Group 1
    Alkaline earth metals : Group 2
    Halogens : Group 17
    Noble gases : Group 18

    ReplyDelete
  125. SalinaFri Nov 06, 10:16:00 AM

    Q NO 30
    The formula to find the maximum number of electrons in an orbit is 2n2 where n is the number of orbit.

    ReplyDelete
  126. SalinaFri Nov 06, 10:17:00 AM

    Q NO 31
    Any two metalloids are Boron and Germanium.

    ReplyDelete
  127. SalinaFri Nov 06, 10:24:00 AM

    Q NO 32
    Metals are considered to be electropositive in nature due to their ability to donate electrons.
    non-metals are electronegative as they generally accept electrons.

    ReplyDelete
  128. SalinaFri Nov 06, 10:27:00 AM

    Q NO 33
    octet is an atom or an ion having a maximum of eight electrons in the outermost shell .
    Duplet is an atom having the maximum of two electrons in the outermost shell.

    ReplyDelete
  129. UnknownFri Nov 06, 11:40:00 AM

    Anuka Puri
    Q no 15
    Mendeleev periodic table is based on properties of elements and weight of atomic element but the modern periodic table is based on atomic number, their fundamental property that decides the properties of elements

    ReplyDelete
  130. UnknownFri Nov 06, 11:53:00 AM

    Anuka Puri
    Q no 16
    There are 4 block in the modern periodic table

    ReplyDelete
  131. UnknownFri Nov 06, 11:55:00 AM

    Anuka Puri
    Q no 17
    Fluorine is more reactive that chlorine because fluorine has a higher electrone getvity

    ReplyDelete
  132. UnknownFri Nov 06, 11:59:00 AM

    Anuka Puri
    Q no 18
    Most reactive non metals fluorine
    Most reactive metal:alkali metals
    (Group 1)
    Noble gases:group 18

    ReplyDelete
  133. UnknownFri Nov 06, 12:04:00 PM

    Anuka Puri
    Q no 19
    Electropositivity can be defined as the tendency of an atom to donate electrons and form positively charged cations

    ReplyDelete
  134. SalinaFri Nov 06, 12:04:00 PM

    Q NO 34
    shape of p orbital is dumbbell shaped and d orbital is cloverleaf shaped.

    ReplyDelete
  135. SalinaFri Nov 06, 12:07:00 PM

    Q NO 35
    The two factors that determine the reactivity of elements are: nuclear charge and atomic radius.

    ReplyDelete
  136. UnknownFri Nov 06, 12:08:00 PM

    Anuka Puri
    Q no 20
    Lonization energy can be defined as the amount of energy required to remove an electron from in isolated atom or molecular

    ReplyDelete
  137. salishmaFri Nov 06, 12:10:00 PM

    2 marks Qno 1
    The table in which the elements are arranged in group or period on the basic of their characteristics is called periodic table

    ReplyDelete
  138. SalinaFri Nov 06, 12:13:00 PM

    Q NO 38
    A halogen is a chemical element that forms a salt when it reacts with metal.

    ReplyDelete
  139. SalinaFri Nov 06, 12:16:00 PM

    Q NO 39
    an element (e.g. arsenic, antimony, or tin) whose properties are intermediate between those of metals and solid non-metals or semiconductors are called metalloids.

    ReplyDelete
  140. salishmaFri Nov 06, 12:19:00 PM

    2 marks qno 2
    the advantage of periodic table are
    1. The classification of elements is based on the atomic number, which is a more fundamental property.
    2. The reason for placing isotopes at one place is justified as the classification is on the basis of atomic number.




    ReplyDelete
  141. SalinaFri Nov 06, 12:20:00 PM

    2 marks question
    Q NO 1
    A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure appear in vertical columns is called periodic table.

    ReplyDelete
  142. salishmaFri Nov 06, 12:24:00 PM

    2 marks qno3
    the vertical column of periodic table is called group

    the horizontal row of periodic table is called period

    ReplyDelete
  143. Ranjita TamangFri Nov 06, 12:24:00 PM

    Q/no 22
    Atomic radius is the distance from the centre ofor the nucleus to the outer most shell containing electrons .

    ReplyDelete
  144. YuginnFri Nov 06, 12:25:00 PM

    Q.no 23

    A valence electron is a negatively charged particle ,located in the outer most shell of an atom.

    ReplyDelete
  145. SalinaFri Nov 06, 12:25:00 PM

    Q NO 2
    The advantages of periodic table are:
    It is easier to remember the properties of an element.
    Periodic table has made the study of chemistry systematic and easy.

    ReplyDelete
  146. YuginnFri Nov 06, 12:27:00 PM

    Q.no.24

    Electronic configuration is the distribution of electrons in different orbits.

    ReplyDelete
  147. Gagan PandeyFri Nov 06, 12:27:00 PM

    21
    electronegativity is the function of atoms to attract the binding pair of electrons

    ReplyDelete
  148. amuna basnetFri Nov 06, 12:27:00 PM

    2 marks que
    Q no 2
    1)It is easier to remember the propertise of an element if its position inthe periodic table is known.
    2)The periodic table has made the study of chemistry systematic and easy.

    ReplyDelete
  149. salishmaFri Nov 06, 12:28:00 PM

    2 marks qno4
    Mendeleev leave many gaps in his periodic table so that it could help in the discovery of new elements



    ReplyDelete
  150. SHEKHAR BISUNKHEFri Nov 06, 12:28:00 PM

    Q NO 39
    an element whose properties are intermediate between those of metals and solid non-metals or semiconductors are called metalloids

    ReplyDelete
  151. Ranjita TamangFri Nov 06, 12:28:00 PM

    Q/ no 23
    VaLance electrons in the outermost shell of the atom that determine an atom's or groups ability to bond with others .

    ReplyDelete
  152. SalinaFri Nov 06, 12:29:00 PM

    Q NO 3
    The horizontal rows of the periodic table are called periods.
    The vetical columns of the periodic table are called groups.

    ReplyDelete
  153. Ranjita TamangFri Nov 06, 12:32:00 PM

    Q/no 25
    Inter gas is a gas that does not undergo chemical reactions under a set of given condition .

    ReplyDelete
  154. Ranjita TamangFri Nov 06, 12:37:00 PM

    Q/no28
    There are 8 group and 7 periods in mendeleev's periodic table .

    ReplyDelete
  155. salishmaFri Nov 06, 12:38:00 PM

    2 marks qno7
    VIIA group of Modern periodic table called halogen because they react with metal to give salt and water

    ReplyDelete
  156. SalinaFri Nov 06, 12:39:00 PM

    Q NO 4
    The mendeleev left many gaps in his periodic table because for the elements which was not known at that time. At that time only 63 elements were known.

    ReplyDelete
  157. Ranjita TamangFri Nov 06, 12:41:00 PM

    Q/no 29
    the group no of akali metals is 1st,alkali earth metals are in 2nd group, halogens are in 17 group and noble metal are in 18 group .

    ReplyDelete
  158. amuna basnetFri Nov 06, 12:41:00 PM

    2 marks
    Q no 3
    The horizontal rows of element are called periods.
    The vertical columns are called groups.

    ReplyDelete
  159. SapanaFri Nov 06, 12:42:00 PM

    Qno17 sapana
    Fluorine is more reactive between fluorine and chlorine because fluorine has a higher electronegativity than chlorine

    ReplyDelete
  160. Ranjita TamangFri Nov 06, 12:44:00 PM

    Q/no 30
    The formula to find the maximum no.of any orbit is 2n2 (square) where n is the no.of orbit .

    ReplyDelete
  161. Gagan PandeyFri Nov 06, 12:45:00 PM

    22
    the distance form the center of the nucleus to the boundary of the surrounding electrons is known as atomic radius

    ReplyDelete
  162. Ranjita TamangFri Nov 06, 12:46:00 PM

    Q/no 31
    Any two metalloids except silicon are:
    1》Germanium
    2》Boron

    ReplyDelete
  163. SapanaFri Nov 06, 12:47:00 PM

    Electropositivity is the positive change of atom to donate electrons

    ReplyDelete
  164. Gagan PandeyFri Nov 06, 12:50:00 PM

    23
    valence electron is the outer shell electron,associated with atom that cna be participate in the form of chemical bond , if the outer shell is not closed .

    ReplyDelete
  165. amuna basnetFri Nov 06, 12:51:00 PM

    2 marks
    Q no 4
    Mandeleev leave many gaps in his periodic table because he predicted that there would be such elements which will fill in the gaps in future.He also predicted the properties of these element.

    ReplyDelete
  166. SapanaFri Nov 06, 12:52:00 PM

    Qno18
    Sapana
    Noble gases are in the group 18 most reactive non metals are in group 17 and most reactive metals are in group

    ReplyDelete
  167. Gagan PandeyFri Nov 06, 12:53:00 PM

    24
    the distribution of electron of an atom or molecule in atomic ,molecular orbitals

    ReplyDelete
  168. Gagan PandeyFri Nov 06, 12:55:00 PM

    25
    helium, neon ,argon ,etc are known as the inert gases

    ReplyDelete
  169. SapanaFri Nov 06, 12:57:00 PM

    Qno30 sapana
    The formula to find the maximum no of any orbit is 2n2(square) where n is the no of orbit

    ReplyDelete
  170. Gagan PandeyFri Nov 06, 12:59:00 PM

    26
    (Ru ) ruthenium , (Rh) rhodium , (Pd) palladium, (Ag) silver are known as the noble metals

    ReplyDelete
  171. Gagan PandeyFri Nov 06, 01:02:00 PM

    27
    the valency of zero group elements is noble gases like argon , neon ,helium etc.

    ReplyDelete
  172. SapanaFri Nov 06, 01:03:00 PM

    Qno34
    Sapana
    Shape of p orbital is dumbbell shaped and d orbital is cloverleaf shaped

    ReplyDelete
  173. Gagan PandeyFri Nov 06, 01:05:00 PM

    28
    eight group and seven periods are there in mendeleev periodic table

    ReplyDelete
  174. UnknownFri Nov 06, 01:22:00 PM

    Anuka Puri
    Q no 21
    Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the bonking electrons

    ReplyDelete
  175. UnknownFri Nov 06, 01:35:00 PM

    Anuka Puri
    Q no 22
    Atomic radius is the typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons.simply atomic radius is the radius of an atom

    ReplyDelete
  176. UnknownFri Nov 06, 04:31:00 PM

    group

    ReplyDelete
  177. UnknownFri Nov 06, 04:33:00 PM

    anuka
    Q no 23
    vatence electron is the outer shell of associated with atom that can be participate in the form of chemical bond if the outer shell is not closed

    ReplyDelete
  178. UnknownFri Nov 06, 04:37:00 PM

    anuka
    Q no 24
    the distribution of electron of an atom or molecule in atomic molecules orbitals

    ReplyDelete
  179. UnknownFri Nov 06, 04:39:00 PM

    anuka
    Q not 25
    helium,neon,argon etc are known as the inert gases

    ReplyDelete
  180. UnknownFri Nov 06, 04:43:00 PM

    anuka
    Q no 26
    ( Ru)ruthenium, (RH)rhodium, (pd) pathadium (Ag) silver are known as the noble metals

    ReplyDelete
  181. UnknownFri Nov 06, 04:45:00 PM

    anuka
    Q no 27
    the valency of zero group elements is noble gases like argon, helium, etc

    ReplyDelete
  182. SapanaFri Nov 06, 05:53:00 PM

    Qno28
    Sapana
    Eight group and seven periods are there mendeleev periodic table

    ReplyDelete
  183. dikshya karkiFri Nov 06, 05:59:00 PM

    q.no.31
    Any two metalloids except silicon are:
    1.Tellurium 2.Silicon

    ReplyDelete
  184. SapanaFri Nov 06, 06:00:00 PM

    Qno 24
    Sapana
    Electronic configuration is the distribution of electrons in different orbits

    ReplyDelete
  185. dikshya karkiFri Nov 06, 06:02:00 PM

    q.no.32
    Metals are considered to be electropositive in nature due to their ability to donate electrons.
    non-metals are electronegative as they generally accept electrons.

    ReplyDelete
  186. SapanaFri Nov 06, 06:06:00 PM

    Qno21
    Sapana
    Electronegativity is the function of atoms to attract the binding pair of electrons

    ReplyDelete
  187. SapanaFri Nov 06, 06:39:00 PM

    Qno38
    Sapana
    A halogen is a chemical element that forms a salt when it reacts what with metal


    ReplyDelete
  188. SapanaFri Nov 06, 06:45:00 PM

    Qno27
    Sapana
    The valency of zero group elements is noble gases like argon belium etc

    ReplyDelete
  189. salishmaSat Nov 07, 04:15:00 PM

    2 marks q no 8.
    IIA group of Modern periodic table is called alkali earth metals because they are found in the earths surface in the form of oxide and react with water to produce alkalis .

    ReplyDelete
  190. salishmaSat Nov 07, 04:19:00 PM

    2 marks q no 9
    VIIIA group of Modern periodic table are called inert elements because they have eight electrons in their valance and donot take part in chemical reaction .


    ReplyDelete
  191. YuginnSat Nov 07, 04:33:00 PM

    Q.no 17

    Fluorine is more reactive than chlorine because fluorine has a higher electronegativity.

    ReplyDelete
  192. salishmaSat Nov 07, 04:34:00 PM

    2 marks q no10.
    classification of elements is considered as the important achievement in the study of chemistery because it makes the study of elements easy, scientific, and practicable .

    ReplyDelete
  193. YuginnSat Nov 07, 04:36:00 PM

    Q.no 21

    Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract to bondoing electrons.

    ReplyDelete
  194. YuginnSat Nov 07, 04:37:00 PM

    Q.no 19

    The tendency of an atom to donate electrons and withdraw from covalent bonds to form positively charged cautions.

    ReplyDelete
  195. salishmaSat Nov 07, 04:39:00 PM

    2 marks q no 11.
    the special features of modern periodic table are
    1.the elements are arranged in order of their increasing atomic number
    2.the elements have been clearly separated .

    ReplyDelete
  196. YuginnSat Nov 07, 04:40:00 PM

    Q.no 22

    Automatic radius is the distance from the center of the nucleus to the outer most shell containing electrons.

    ReplyDelete
  197. YuginnSat Nov 07, 04:45:00 PM

    Q.no 29

    The group number of alkali metal is 1st alkali earth metals are in 2nd group, halogens are in 17 group and noble metal are in 18 group.

    ReplyDelete
  198. YuginnSat Nov 07, 04:48:00 PM

    Q.no 30

    The formula to find the maximum number of any orbits is 2n2( square) where n is the number of orbits.

    ReplyDelete
  199. YuginnSat Nov 07, 04:50:00 PM

    Q.no 31

    Any two metallodis expect silicon are:-
    1) Germanium
    2) Boron

    ReplyDelete