What is the smallest particle of an element called?

The smallest particle of an element is called an atom. An atom consists of a nucleus made up of protons and neutrons, surrounded by electrons that orbit the nucleus. Atoms are the fundamental building blocks of matter and retain all the chemical properties of the element they represent.

For example, a single atom of carbon remains carbon regardless of its state or size. Atoms combine to form molecules, which are groups of two or more atoms bonded together. However, when referring specifically to an individual particle representing an element, the term "atom" is the appropriate choice since it defines the substance in its purest form.

Other terms such as molecule, ion, and particle have different meanings in the context of chemistry. A molecule refers to two or more atoms bonded together, an ion is an atom or molecule that has gained or lost one or more electrons, resulting in a charge, and the term particle is a more general term that can refer to any small localized object. Therefore, atom is the most precise answer to the question regarding the smallest unit of an element.