Since one molecule of K2SO4 contains 7 atoms {Two Potassium(K), One Sulphur (S) and Four Oxygen (O)}.
Thus in 5 moles there will be,
6.022 × 10²³ × 7 × 5 =
210.77 × 10²³ or 2.1077 × 10²⁵ or 21077 × 10²¹ atoms.
Here, 6.022 × 10²³ is the Avogadro number