Question

In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed?

Answer 1

Noble gas configuration:

• The general electronic configuration of the noble gases is given as ‘${\mathrm{ns}}^2{\mathrm{np}}^6’$, so it has 8 valence electrons.
• Therefore, the outermost valence shells of the noble gases can be considered ‘full’ which is the reason for the chemically inert nature of the elements obtaining inert gas configuration.

Charge on the ion formed if $\mathrm{X}$ acquires noble gas configuration:

• The outermost shell of the given element $\mathrm{X}$ has 6 electrons in its valence shell.
• Hence to attain the noble gas configuration, two more electrons are required.
• So, to obtain a noble gas configuration the element must accept two electrons and therefore its charge will be $-2.$
• $\mathrm{X}+2{\mathrm{e}}^{-}\to {\mathrm{X}}^{2-}$

Hence, if the element acquires a noble gas configuration by accepting a requisite number of electrons, then the charge on the ion so formed would be $-2.$