Question

Why does calcium have a larger atomic radius than magnesium

Answer 1

Down the group , atomic radius of atoms increase due to increase in number of shells there by increasing shielding effect and decreasing effective nuclear charge . ( effective nuclear charge pulls the valence shell closer to the nucleus)

Answer 2

Answer: So To sum that up magnesium nucleus will attract the electrons more toward it and therefore, shrinking the size of the atom.

Explanation: Magnesium nucleus will attract the electrons more toward it and therefore, shrinking the size of the atom. Magnesium atom is smaller than Calcium atom because Calcium has more electron ( 20e− ) which will occupy more energy levels ( n=4 for Calcium versus n=3 for Magnesium).