Draw the atomic orbit structure diagram for formation of -

(a) hydrogen molecule

(b) chlorine molecule

(c) oxygen molecule

(d) nitrogen molecule

[at. no. H=1, Cl=17, O=8, N=7]

Give reasons for formation of single covalent bond between two chlorine atoms and a double covalent bond between two oxygen atoms - during formation of a covalent chlorine molecule and formation of a covalent oxygen molecule, respectively.

With the help of an atomic orbit structure diagram - explain the formation of :

(a) carbon tetrachloride

(b) methane

[at. no. : C=6, Cl=17, H=1]

State why water has two lone pairs of electrons in it's covalent molecule while ammonia has one lone pair.