Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Which statement best describes an atom?

1. An atom is a particle in motion

2. An atom is the basic unit of an element

3. An atom is a compound of several molecules

4. An atom is a component of a cell

The correct answer is: An atom is the basic unit of an element

An atom is indeed the basic unit of an element, which is fundamental to understanding the structure of matter in chemistry. This statement recognizes that atoms are the smallest units that retain the properties of an element. Each element on the periodic table is composed of atoms that contain a nucleus made up of protons and neutrons, surrounded by electrons. This understanding is crucial in various fields, including chemistry, biology, and physics, as elements are the building blocks for all substances. In contrast, describing an atom as a particle in motion doesn't capture its defining characteristics, and stating it as a compound of several molecules misrepresents its fundamental nature, as a compound is formed from two or more different atoms bonded together. Lastly, while atoms are indeed components of cells, the statement does not sufficiently clarify their role as the fundamental units of elements, which is essential for understanding both biological systems and chemical reactions.