Answer:
If an atom gain or lose electron it will do the same thing to and from its outer orbital.
Explanation:
An atom consist of protons,neutrons and electrons. Protons and neutrons are present inside the nucleus whereas the electrons are present in various orbitals have varying length from the nucleus.
The outer orbital is weakly attracted by the nucleus as a result the orbital take part in a chemical reaction.
When this atom mentioned in the question will gain electron the additional or gained electron will enter the outermost orbital and gives atom one unit negative charge.
By the same way when this atom lose electron that electron will be liberated from the outer most orbital.As a result the atom will gain one unit positive charge.
