How do anions typically form?

Anions typically form through the gain of electrons. When an atom acquires one or more additional electrons, it becomes negatively charged because the overall number of electrons exceeds the number of protons in the atom. This imbalance of charge results in an anion, which is essentially a negatively charged ion.

In contrast, gaining protons would increase the positive charge of the atom, thus forming a cation rather than an anion. Losing neutrons does not directly affect the charge of the atom; neutrons are neutrally charged and only alter the atomic mass. Sharing electrons is characteristic of covalent bonding, where atoms combine to form molecules, but it does not create anions since there is no net gain of electrons that leads to an overall negative charge.