Answer: B.) A cation
Explanation: Sodium is an element with atomic number 11 and thus contain 11 electrons. It is a s block element as the last electron enters the s orbital. The nearest noble gas is Neon with 10 electrons.
The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration is:
Sodium atom will loose one electron to gain noble gas configuration and form sodium cation with +1 charge.
![[Na^+]:10:1s^22s^22p^63s^0](https://img.qammunity.org/2017/formulas/biology/high-school/fgb7kq1xrapd1myr5b8wy1hbf9aiu3bll4.png)
An anion is formed when a neutral atom gains electron.
An inert gas is a neutral element with completely filled valence shell.
A covalent bond is formed by sharing of electrons between two atoms.