Final answer:
Atoms have an electrical charge that is determined by the balance of their protons and electrons. Atoms are electrically neutral when these numbers are equal, but they become ions with either a positive or negative charge when the numbers are unbalanced due to chemical reactions.
Step-by-step explanation:
The type of electrical charge an atom has depends on the balance between its positively charged protons, found in the nucleus, and its negatively charged electrons, which orbit the nucleus. In a neutral atom, the number of protons (p+) is equal to the number of electrons (e-), which makes the overall charge balanced and thus, the atom is electrically neutral. An atom becomes an ion when it either loses electrons and becomes positively charged, known as a cation, or gains electrons and becomes negatively charged, known as an anion.
An atom's neutrons have no charge, maintaining electrical neutrality within the nucleus. During achemical reactions, atoms often seek to have a full valence shell, leading them to gain or lose electrons, thereby altering the balance of charges. This change causes the atom to become a positively or negatively charged ion, depending on whether it loses or gains electrons respectively.