According to Avogadro's number we have 6.022 * 10²³ atoms in one mol of atoms. Then:
1 mol of atoms = 6.022 * 10²³ atoms
We have to find the number of atoms that are present in 0.350 moles of Zn. So:
number of atoms of Zn = 0.350 moles of Zn * 6.022 * 10²³ atoms of Zn/(1 mol of Zn)
number of atoms of Zn = 2.11 * 10²³ atoms of Zn
The answer to our problem is 2..11 * 10²³ atoms of Zn