Answer :
It is the process of reduction. If you want to remember it, I recommend remember that gaining electrons 'reduces' charge, by increasing the negative number... If that makes sense XD
Answer: Option (3) is the correct answer.
Explanation:
In the process of oxidation, an atom loses electrons or an increase in oxidation number of the atom occurs.
For example, [tex]Cu(s) \rightarrow Cu^{2+}(aq) + 2e^{-}[/tex] is an oxidation process.
Whereas in a process of reduction, an atom gain electrons or a decrease in oxidation number of the atom occurs.
For example, [tex]2Ag^{+} + 2e^{-} \rightarrow 2Ag(s)[/tex] is a reduction process.
Thus, we can conclude that the chemical process in which electrons are gained by an atom or an ion is called reduction.