Question

1. a) Explain why all the periods in the periodic table do not have the same number of elements

in them.

(5)

b) Explain the variation in ionization energy across the elements of period 2 in the periodic

table.

(5)

2. a) What is effective nuclear charge? What is its role in explaining the size of atoms? (5)

b) What is hydrogen bonding? Differentiate between intermolecular and intramolecular

hydrogen bonding.

(5)

3. a) Explain the trends in the thermal stability of the oxosalts of alkali and alkaline earth

metals.

(5)

b) Complete the following reactions and balance them: (5)

(i) B + H2SO4 (concentrated) 

(ii) LiBH4 + H2O 

4 a) Why is borazine called “inorganic benzene”? Explain. (5)

b) Compare the electronic structure of N atom in trimethylamine and trisilylamine. (5)

5. a) Write the structures of pyrosilicates and chain silicates. (5)

b) Describe the principle of manufacture of sulphuric acid by contact process. What are the

limitations of this process and how are these overcome?

(5)

6. a) Explain the paramagnetic nature of oxygen molecule using molecular orbital theory. (5)

b) What were the difficulties in the preparation of fluorine? Explain how these difficulties

were overcome.

(5)

7. a) Name the oxoacids of halogens. How does the strength of oxoacids vary with the change

in the oxidation state of halogens and down the group? Explain.

(5)

b) Why are the fluorides and oxides of Kr, Xe and Rn the only binary compounds of the

noble gases? Why similar compounds are not formed by He and Ne?

(5)

8. a) What is the importance of beneficiation of ores? List various methods used for the same. (5)

b) When electrons are added in the 6s orbital, what happens to the energy level of the 5d

orbitals? As a result after the electron enters 5d orbitals in the lanthanum, in which orbital

does the next electron enter in cerium?

(5)

9. a) Even though actinides show similar variations in magnetic properties as that of

lanthanides, their magnetic properties are more complicated. Explain.

(5)

b) Explain the experimental facts that cannot be explained by the simple model of Werner’s

theory.

(5)

10. a) How can one decide whether the high spin or the low spin configuration of a metal

complex will be more stable? Elaborate.

(5)

b) Why it is advisable to always reduce the minerals in order to extract metals from them?

Give the specific properties of magnalium.


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Answer 1

Answer:

because mousely made the periodic table like that manner

Explanation:

Answer 2

Answer:

1.All the periods in the periodic table do not have the same number of elements in them as the number of elements in a period is determined by the quantum numbers. For example: The first period has two elements only since the 1s orbital gets filled.