Final answer:
An atom with an unbalanced number of protons and electrons is called an ion. It becomes positively charged (cation) if it loses electrons and negatively charged (anion) if it gains electrons. This process is called ionization.
Step-by-step explanation:
An atom that has an electrical charge due to having a number of electrons unequal to the number of protons is considered a ion. When an atom does not contain equal numbers of protons and electrons, it has a net charge and becomes an ion. There are two types of ions: if the atom loses electrons, resulting in more protons than electrons, it becomes a positively charged ion known as a cation. Conversely, if the atom gains electrons, resulting in more electrons than protons, it becomes a negatively charged ion called an anion. The process by which an atom becomes an ion is referred to as ionization.
Atoms are normally electrically neutral when they have an equal number of protons and electrons. The charges from the protons and electrons cancel each other out, leading to no net charge. However, when this balance is disrupted by the loss or gain of electrons, the atom becomes electrically charged and thus is referred to as an ion. The electromagnetic force plays a role in this, as it causes the negatively charged electrons to be attracted to the positively charged protons, while repulsion between like charges contributes to the stability of the atomic nucleus due to the nuclear force.