Question

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

Answer 1

simply put... sulfur has the greater mass because it has greater number of protons, neutrons, and electrons which make up more mass than the less number of protons, neutrons, and electrons within carbon

Answer 2

Mole is given as,
Mole = mass / M.mass

M.mass of Carbon = 12.01 g/mol

M.mass of Sulfur = 32.06 g/mol

Solving mass for both element keeping number of moles equal to one,

For Carbon;
Mass = Mole × M.mass

Mass = 1 mol × 12.01 g/mol

Mass = 12.01 g

For Sulfur:
Mass = 1 mol × 32.06 g/mol

Mass = 32.06 g

Result:
Hence, 1 mole of Carbon has smaller mass than 1 mole of Sulfur because the M.mass of Carbon is smaller than Sulfur due to less number of protons and neutrons in its nucleus.