Why does one mole of carbon atoms have a smaller mass than one mole of sulfur atoms?

To determine this, you can look at the molecular weight of that particular atom which is found on the periodic table. Carbon has a molar mass of 12.01 grams / mole. Sulfur has a molar mass of 32.06 grams / mole. This means one mole of carbon weighs 12.01 grams and one mole of sulfur weighs 32.06 grams. Therefore, one mole of carbon atoms has a smaller mss than one mole of sulfur atoms.