1 One mole of a substance contains the same number of atoms or molecules as one mole of any other substance.
a Which contains more atoms: 56 g of Fe or 16 g of S? Show your working.

a) Fe contains more atoms.

Explanation:

To find the number of moles we divide by the molar mass:-

56g of iron (Fe) = 56/55.845 = 1.0028 moles

16g of Sulphur (S) = 16/32.06 = 0.6938 moles.

So 56g of Fe contains more atoms.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.