Which of the following has the smallest number of atoms?

The correct option is D $1g$ of $C{O}_2$

$44gC{O}_2$ has $3N_A$ atoms.

$\therefore 1g$ of $C{O}_2$ has $\frac{3N_A}{44}$ atoms or $0.068N_A$ atoms

$114g$ of $C_8{H}_{18}$ has $26N_A$ atoms

$1g$ of $C_8{H}_{18}$ has $\frac{26N_A}{114}$ atoms

$=\frac{13N_A}{57}$ atoms or $0.23N_A$ atoms

$30g$ of $C_2{H}_6$ has $\frac{8N_A}{30}$ or $\frac{4N_A}{15}$ atoms

$26g$ of $LiF$ has $2N_A$ atoms

$\therefore 1g$ of $LiF$ has $\frac{2N_A}{26}$ or $\frac{N_A}{13}$ or $0.08$ atoms

Therefore, $1g$ of $C{O}_2$ has the smallest number of atoms.