Answer
(a) $1.79\times10^{-22}\,g$
(b) $6.49\times10^{-23}\,g$
Work Step by Step
(a) Molar mass of Ag=$107.8682\,g/mol$
That is, the mass of $6.022\times10^{23}$ Ag atoms is equal to 107.8682 g.
$\implies$mass of 1 Ag atom=$\frac{107.8682\,g}{6.022\times10^{23}}=1.79\times10^{-22}\,g$
(b) Molar mass of K=$39.0983\,g/mol$
That is, the mass of $6.022\times10^{23}$ K atoms is equal to 39.0983 g.
$\implies$mass of 1 K atom=$\frac{39.0983\,g}{6.022\times10^{23}}=6.49\times10^{-23}\,g$
