Answer: The sodium ion has a smaller radius than the atom.
Explanation:
Atomic radii is the distance from the center of the nucleus to the valence shell.
Sodium atom being neutral has 11 protons and 11 electrons.
Sodium ion has 10 electrons and 11 protons. Now 11 protons present in the nucleus can easily influence 10 electrons towards itself, the effective nuclear charge increases, the valence electrons are more tightly held by the nucleus and thus the size decreases.
Energy Levels of Electrons. As you may remember from chemistry, an atom consists of electrons orbiting around a nucleus. ... They are restricted to orbits with only certain energies. Electrons can jump from one energy level to another, but they can never have orbits with energies other than the allowed energy levels.
