Humber Admissions Practice Test

The correct choice accurately identifies anions as negatively charged ions. Anions form when atoms gain one or more electrons, which leads to an excess of negative charge due to the added electrons. This process typically occurs in ionic compounds, where nonmetals often gain electrons from metals, resulting in the formation of anions.

In contexts within chemistry, the term "anion" specifically refers to any ion with a negative charge. This distinguishes them from cations, which are positively charged ions formed when atoms lose electrons.

The other options describe different concepts. Positively charged particles refer to cations, not anions. Particles that share electrons pertain to covalent bonding rather than ionic forms. Atoms that are not ions refer to neutral atoms, which don't necessarily convey the characteristics associated with anions. Understanding the definition and characteristics of anions is crucial for grasping concepts related to charge, bonding, and compounds in chemistry.