AFOQT Practice Test 2026 - Free AFOQT Questions and Complete Study Guide

The smallest particle of an element that retains its identity is indeed an atom. Atoms are the basic building blocks of matter and represent the fundamental units of an element. Each element is defined by the type of atom it contains, characterized by its number of protons, electrons, and neutrons.

When we consider the other options: a molecule refers to two or more atoms bonded together, which can be of the same or different elements; a compound is a substance formed when two or more different elements combine in fixed proportions, thus requiring multiple atoms from different elements. An ionic bond describes the electrostatic attraction between oppositely charged ions, which occurs between atoms but does not denote an individual particle that retains the identity of an element.

Therefore, the atom is the only option that represents a single particle of an element capable of retaining all the chemical properties that define that element.