Answer
$2.6\times 10^{24}~~$ atoms
Work Step by Step
We can find the mass of one atom:
$m = 235~u$
$m = (235)~(1.66\times 10^{-27}~kg)$
$m = 3.901\times 10^{-25}~kg$
We can find the number of atoms in 1.0 kg:
$\frac{1.0~kg}{3.901\times 10^{-25}~kg} = 2.6\times 10^{24}$
