Question

The sodium atom loses an electron to form a sodium ion (Na+). Which statement is correct with respect to its atomic radius?

Answer 1

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.

$Na:11:1s^22s^22p^63s^1$

Sodium atom being neutral has 11 protons and 11 electrons.

$Na^+:10:1s^22s^22p^6$

Sodium ion $Na^+$ 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.

Answer 2

The sodium ion has a smaller radius than its atom