Fill in the blanks from the choices given :

The polar covalent compound in gaseous state that does not conduct electricity is …………… [carbon tetrachloride, ammonia, methane].

Draw the electron dot diagram for the compounds given. Represent the electrons by [.] and [x] in the diagram.

[Ca=20, O=8, Cl=17, H=1]

(i) Calcium oxide

(ii) Chlorine molecule

(iii) Water molecule

Draw the geometrical atomic structure representing the electronic configuration of atoms of elements of :

1. Period-2
   1. group 14 [IVA] — carbon [at no. 6]
   2. group 15 [VA] — nitrogen [at. no. 7]
   3. group 16 [VI A] — oxygen [at no. 8]
2. Period-3
   1. group 1[IA] — sodium [at no. 11]
   2. group 2[IIA] — magnesium [at. no. 12]
   3. group 17[VIIA]— chlorine [at. no. 17]
3. Period-4
   1. group 2[IIA] — calcium [at. no. 20].

What is meant by the term 'chemical bond' and 'chemical bonding'.