C8 Matter
1. Define matter.
2. In whose principle does the modern chemistry based on?
3. Write down the postulates of John Dalton.
4. Define atom and ion.
5. What do you mean by molecules and compound? Give some examples.
6. Define element with example.
7. What is a mixture? Write its types.
8. Describe atomic structure with figure.
9. What are protons, electrons and neutrons?
10. What do you mean by atomic number and atomic weight?
11. What is electronic configuration?
12. Write the formula to fill maximum number of electrons in the k, l, m and n shell.
13. Draw the electronic configuration of first 20 elements.
14. Define symbol and valency.
15. What are radicals?
16. What do you mean by electropositive and electronegative radicals? Give some examples.
17. What is a periodic table?
18. State the Mendeleev’s periodic law and modern periodic law.
19. What is a molecular formula?
20. What are the information obtained from molecular formula?
21. Define chemical reaction and equation.
22. What do you mean by word equation?
23. What do you mean by H2 and 2H?
24. What are the basis of making symbols? Give some examples.
25. What are groups and periods of a periodic table?
26. The molecular formula of water is H2O. What do you mean by it?
Posts
Qno1(samikshya phuyal)=matters is anything that occupies space and has mass and can perceived by our physical senses.
ReplyDeleteQno2(samikshya phuyal)=the modern chemistry based on the principal given by john dalton in 1808.
ReplyDeleteQno3(samikshya phuyal)=the main postulates of john dalton are:
ReplyDeletea)matter is composed of a number of extremely small particals called atoms which cannot be further subdivided.
b)atoms of the same element are identical in all respect but different form those of others elements.
c)combination between atoms take place in small whole number resulting in the formation of 'compounds atoms'.
d)the compound atoms of the compound are identical in all respects.
e)an atom can neither be created nor be destroyed.
Qno4(samikshya phuyal)=an atom of an element is defined as the smallest particale of it that can react or combine chemically .
ReplyDeletea charged particales (atom ,molecules,radicales etc)is called an ion.
Q12 Sandhya khatiwada:Matter is anything that occupies space and has mass and can be perceived by our own physical senses.
ReplyDeleteQ2 Sandhya khatiwada:Modern world of Chemistry is based on the principles given by John Dalton in 1808.
ReplyDelete
ReplyDeleteQ3 Sandhya khatiwada : The he main postulates of john dalton are:
_ matter is composed of a number of extremely small particles called 'Atoms' which cannot be further subdivided.
_ Atoms of the same element are identical in all respect but different form those of others elements.
_ Combination between atoms take place in small whole number resulting in the formation of `compound atoms'.
_ The compound atoms of the compound are identical in all respects.
_ An atom can neither be created nor be destroyed.
Q4 sandhya khatiwada: An atom of an element is defined as the smallest particle of it that can be react or combine chemically .
ReplyDelete_ A charged particle (atom,molecule,radical etc.)is called and ion.
Q5 sandhya khatiwada :Molecule of an element or compound is the smallest particle of it that is stable and capable of independent existence .A molecule is made up of two or more than two atoms. For example :H2O (water),co2 (carbon dioxide)etc
ReplyDelete_ A compund is defined as a form of matter,every sample of which is homogeneous and composed of two or more than two elements combined in fixed proportion by weight.For example:zinc chloride(zncl2),sodium chloride (NaCl)(common salt),zinc sulphate (znso4),etc
Q6 sandhya khatiwada:An element is the distinct kind of matter which can neither be broken down into anything simpler by ordinary chemical means nor built up from any simpler form of matter. For example:Gold,Helium,Hydrogen,Oxygen etc.
ReplyDeleteQ7 Sandhya khatiwada:Two or more than two substances when brought together, do not undergo chemical change but simply lie together and retain their identity,the resulting mass is called a mixture. For example:salt solution,sugar solution,etc .There are two types of mixtures.They are :
ReplyDelete_Homogeneous mixture
_ Heterogeneous mixture
Q9 Sandhya khatiwada:proton is a particle which has a unit positive charge and the mass about the same as that of hydrogen atom.
ReplyDelete_A neutron is an electrically neutral sub_atomic particle with a mass almost the same as that of a proton.
_An electron is negatively charged particle of very small mass .
Q10 sandhya khatiwada :The number of electrons or the number of protons in an electrically neutral atom is called atomic number.
ReplyDelete_The atomic weight of an atom is the weight of protons and neutrons or the weight of the nucleus.
Q11 sandhya khatiwada:The distribution of electrons in different orbits is known as electronic configuration.
ReplyDelete
ReplyDeleteQ12 Sandhya khatiwada :The formula to fill maximum number of electrons in the k, l, m and n shell are given below:
1.The maximum number of electrons in an orbit is given by the formula 2n2 rule where n is the number of orbits.
1st orbit , n =1,no.of electrons =2n2 =2 ×(1)2=2
2nd orbit , n =2 ,no of electrons =2n2 =2×2(2)=8
3rd orbit, n=3 ,no of electrons =2n2 =2 ×3(2)=18
4th orbit , n =,4 no of electrons =2n2 =2 ×4(2)=32
2) The maximum number of electrons on the outermost orbit shall not have more than 8 and next to the outermost not more than 18 .
Q14 sandhya khatiwada:symbol is defined as the shorthand sign of the full name of an element.
ReplyDelete_Valency is defined as the 'combining capacity of an atom for another'.
Q15 sandhya khatiwada: A radical is an atom or group of atoms which maintain their integrity throughout a series of reactions and can be introduced or expelled from combination without any change,
ReplyDeleteQ16 Sandhya khatiwada:Those elements or radical which collect at the positive electrode during electrolysis of their salts ,are electronegative i.e they carry negative charge and therefore move to the positive electrode . For example:Iodide(I)- Borate (Bo3)---etc
ReplyDelete_ Others which are liberated at the negative electrode are supposed to carry positive charge and therefore, are called electro positive radicals.
For example:zn(zinc)++,silver(Ag)+etc
Q17 sandhya khatiwada:The elements are arranged in row and columns in a table by certain rules called periodic table. The rows are groups and columns are periods .
ReplyDeleteQ19 sandhya khatiwada: The molecular formula of a compound is defined as the symbolic representation that shows the actual number of atoms of different elements present in one molecule of the compound .
ReplyDeleteQ20 sandhya khatiwada :The information obtained from molecular formula are given below:
ReplyDelete1. Molecular formula represents one molecule of the substance..
2.It gives the actual number of atoms of each element present in one molecule ...
3.It shows the combining capacity of its component elements ...
4.It helps to know about the molecular weight of the substance...
Q21 sandhya khatiwada: The exchange,combination or decomposition that occurs ih the molecules of matters during a chemical change is called chemical reaction.
ReplyDelete_A chemical equation may be defined as the symbolic representation of a chemical reaction in terms of symbols and formulae.
Q22 sandhya khatiwada: The representation of a chemical change by writing the full names of the reactants and products is called word equation.
ReplyDeleteQ23 sandhya khatiwada:2H means two separate hydrogen atoms.
ReplyDelete_ H2 means a single molecule consisting of two hydrogen atoms bound to each other.