An atom has only one electron more than the nearest noble gas configuration.

What type of ion would it tend to form?

• An atom that has only one electron more than the nearest noble gas configuration will try to lose an electron to gain noble gas configuration and also to attain stability. So, atoms will lose an electron and form a cation (positive ion).

Example:- The Sodium atom (atomic number 11) has an electronic configuration of 2, 8, 1. As a result, its valence shell only possesses one electron and to attain the noble gas configuration of Neon (2, 8) Sodium loses an electron as shown below.
$\mathrm{Na}\stackrel{\mathrm{loses}\mathrm{electron}}{\to }{\mathrm{Na}}^{+}+{\mathrm{e}}^{-}$