$a)Monovalentmaterial$

 $1$ eq. mass of the substance requires $96500$ coulombs

Since the element is monatomic, thus equivalent mass = molecular mass

$6.023\times 10^{23}$ atoms require $96500C$

$1$ atoms require $=\frac{96500}{6.023\times 10^{23}}C=1.6\times 10^{-19}C$

$(b)Divalentmaterial$

Since the element is diatomic, thus equivalent mass $=\frac{molecularmass}{2}$

$=\frac{1\times 6.023\times 10^{23}}{2}$ atoms require $96500C$

$1$ atoms require $=\frac{96500\times 2}{6.023\times 10^{23}}C=3.2\times 10^{-19}C$