Question #0442e

1 Answer
Feb 4, 2018

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

Explanation:

See the image below
www.learner.org/courses/chemistry/images/lrg_img/Mg_NaElectronShellsjpgwww.learner.org/courses/chemistry/images/lrg_img/Mg_NaElectronShellsjpg

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

MgMg 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 MgMg exerts more attractive force than NaNa and thus the size of MgMg is smaller than NaNa.