The diameter of zinc atom is 2.6 A

The diameter of zinc atom is 2.6 A. Calculate
(i) radius of zinc atom in pm and
(ii) number of atoms present in a length of 1.6 cm if the zinc atoms are arranged side by side lengthwise

(i) Diameter of Zn atom = 2.6 A = 2.6 X ${{10}^{-10}}$ m
Radius of Zn atom = 2.6 x ${{10}^{-10}}$ m /2 = 130 pM
(ii)Given, length = 1.6 cm= 1.6x ${{10}^{-2}}$m
Number of Zn atoms in 1.6 x${{10}^{-2}}$ m
= 1.6 x ${{10}^{-2}}$ / 2.6 ${{10}^{-10}}$ = 6.154 x ${{10}^{-7}}$ atoms