Question

Question #0442e

Answer 1

Na is bigger than Mg because of one less proton in the nucleus to attract the outermost electron cloud

Explanation:

See the image below

`Na` has 11 electrons and 11 protons thus it has the less effect on the outermost electron cloud.

`Mg` has 12 electrons and 12 protons, here there is an increase in proton number in the nucleus without any increase in the orbitals. the nucleus of `Mg` exerts more attractive force than `Na` and thus the size of `Mg` is smaller than `Na`.