A Level Chemistry OCR Practice Exam

Which statements correctly describe an anion?

1. A neutral ion with no charge

2. A negatively charged ion

3. A positively charged ion

4. A molecule with an overall positive charge

The correct answer is: A negatively charged ion

An anion is defined as a negatively charged ion, which means it has more electrons than protons. This excess of electrons gives the anion its negative charge, distinguishing it from cations, which are positively charged ions formed by the loss of electrons. The first choice describes a neutral ion, which would not be considered an anion since it lacks any charge. The third choice mischaracterizes an anion by stating it is positively charged, which contradicts the fundamental definition. The fourth choice refers to a molecule with an overall positive charge, again incorrectly categorizing it, as anions specifically refer to species with excess negative charge. Thus, the correct characterization of an anion is that it is a negatively charged ion.