Why does the density of group 2 metals increase?

Answer 1

The density of group 2 metals increases as you go up the group. This is because atomic radius decreases as you go up the group. Density is mass / volume and the ratio of mass to volume of atoms of the elements goes up with the decrease in radius.

Answer 2

The density of Group 2 metals increases as you move down the group because the atomic radius of the metals increases, leading to more electrons and a larger Atomic Mass per unit volume. This results in a higher density due to more mass being packed into the same volume.