Draw molecular configuration of oxygen molecule.

Explain the term hybridization. What are the shapes of $\mathrm{sp}, {\mathrm{sp}}^2$ and ${\mathrm{sp}}^3$ hybrid orbitals? 

State four physical properties that can be used to distinguish between covalent and ionic compounds. Discuss with examples. 

Explain with examples the term electrovalency, covalency and co-ordinate valency.

What is covalent bond? Explain why the covalent bonds between oxygen and hydrogen atoms in water molecule are polar.

Write notes on Co-ordinate bond