(a) Name the process by which particle gains or loses electrons.

Ionization process

• The process of gaining or losing electron(s) is known as the ionization process.
• As a consequence of this loss/gain, an ion's electronic configuration becomes identical usually to that of the corresponding noble gas.

Anions

• When atoms gain electrons, negatively charged $\left(-\right)$ particles known as anions are formed.
• For example, chlorine $\left(\mathrm{Cl}\right)$ gains one electron to form the corresponding anion, chloride ion $\left({\mathrm{Cl}}^{-}\right)$.
• $\mathrm{Cl}+{\mathrm{e}}^{-}\to {\mathrm{Cl}}^{-}$

Cations

• When atoms lose electrons, positively $\left(+\right)$ charged species known as cations are formed.
• For example, Sodium $\left(\mathrm{Na}\right)$ loses one electron to form the corresponding cation, monovalent sodium ion $\left({\mathrm{Na}}^{+}\right)$.
• $\mathrm{Na}\to {\mathrm{Na}}^{+}+{\mathrm{e}}^{-}$

Hence, ionization is the process of losing or gaining electrons.