5.0 × 10^21 atoms of sulfur
We need to know that 1 mole of an element contains atoms equivalent to the Avogadro's number.
Therefore;
1 mole of an element = 6.022 × 10^23 atoms
Thus, 1 mole of sulfur = 6.022 × 10^23 atoms
But, molar mass of sulfur = 32.065 g/mol
This means;
32.065 g contain 6.022 × 10^23 atoms
Therefore, 2.66 g of Sulfur will contain;
= (2.66 g ÷ 32.065 g/mol) × 6.022 × 10^23 atoms
= 5.0 × 10^21 atoms
