AFOQT Practice Test

Which term describes atoms of the same element with different numbers of electrons?

1. Ions

2. Isotopes

3. Compounds

4. Allotropes

The correct answer is: Ions

The correct term for atoms of the same element that have different numbers of electrons is ions. Ions are formed when atoms gain or lose electrons, resulting in a net charge. If an atom loses one or more electrons, it becomes positively charged and is called a cation. Conversely, if it gains electrons, it becomes negatively charged and is referred to as an anion. This variation in the number of electrons affects the atom's charge but not its identity as a specific element. Isotopes, on the other hand, refer to atoms of the same element that have the same number of protons but differ in the number of neutrons. This does not involve a change in the number of electrons. Compounds consist of two or more different elements chemically bonded together, which is not related to the change in electron numbers within a single element. Allotropes are different structural forms of the same element in the same physical state, like carbon existing as diamond or graphite, again unrelated to electron variation. Thus, ions accurately describes the concept of variations in electron count for atoms of the same element.