In the formation of (i) Oxygen molecule (ii) Carbon tetrachloride molecule, state the following:

(a) Electronic configuration of nearest inert gas attained.

(b) How many electrons are shared/transferred in bond formation?

(c) Which type of bonds these compounds form?

(d) Draw the orbital diagrams?

(a) What are free radicals ?
(b) How are they formed ?
(c) Why are free radicals unstable ?
(d) Give an example of free radical formation.

A sample of an element A contains two isotopes ¹⁶₈A and ¹⁸₈A. If the average atomic mass of the element is 16.2 amu, calculate the percentage of the two isotopes in this sample.

An atom having mass number 13 has 7 neutrons. What is the atomic number of the atom ?