2.37 The diameter of zinc atom is 2.6 Å.Calculate

(a) radius of zinc atom in pm and
(b) number of atoms present in a length of 1.6 cm if the zinc atoms are arranged side by side lengthwise.

(a) Radius of zinc atom = Diameter/2

= 2.6 A2
= 1.3 x 10-10 m
= 130 x 1012 m = 130 pm

(b) Length of the arrangement = 1.6 cm
= 1.6 × 10-2 m
Diameter of zinc atom = 2.6 × 10-10 m
∴ Number of zinc atoms present in the arrangement

= 1.6 x 10-2 m2.6 x 10-10 m
= 0.6153 x 108 m
= 6.153 x 107