Final answer:
Anions formed from a single atom end with the suffix '-ide' and are known as monatomic anions. The charge corresponds with the number of electrons gained to reach a noble gas electron configuration.
Step-by-step explanation:
Anions formed from a single atom typically end with the suffix -ide. These are called monatomic anions. For example, a fluoride ion is denoted as F¯ and is a single atom of fluorine that has gained an electron. Similarly, an oxygen atom gains two electrons to become an oxide ion, O²¯. This naming convention applies generally to nonmetals that gain electrons in order to achieve a stable electron configuration resembling that of the nearest noble gas.
The charge on an anion correlates with the number of electrons gained. Group 17 elements, like chlorine, gain one electron to become an anion with a 1− charge. Group 16 elements, such as oxygen, gain two electrons to form anions with a 2− charge, and Group 15 elements gain three electrons for a 3− charge. The formation of these anions can be determined by analyzing the electron configuration of the atom and determining how many additional electrons are needed to reach the next noble gas configuration.