Kaplan Nursing Entrance Practice Exam

What is an atom that is not electrically neutral called?

1. Isotope

2. Ionic compound

3. Ion

4. Molecule

The correct answer is: Ion

An atom that is not electrically neutral is referred to as an ion. This occurs when an atom has either gained or lost one or more electrons, resulting in a net electrical charge. If an atom loses electrons, it becomes positively charged and is called a cation. Conversely, if it gains electrons, it becomes negatively charged and is known as an anion. The defining characteristic of an ion is this imbalance between the number of protons and electrons, which leads to the positive or negative charge. In contrast, isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, thus differing in atomic mass but remaining electrically neutral. An ionic compound consists of ions held together by ionic bonds, formed when atoms transfer electrons, but it is a molecule made up of ions rather than just a single charged particle. A molecule refers to two or more atoms chemically bonded together, which can be neutral or charged, but again does not define an atom that is not electrically neutral. Thus, the term that fits the description of an atom that lacks electrical neutrality is ion.