What is an atom?

An atom is fundamentally defined as the smallest unit of an element that retains all the properties of that element. This definition highlights the atom's role as the building block of matter, which is crucial in understanding the composition and behavior of different substances. Each element in the periodic table consists of unique atoms that define their chemical properties, such as reactivity, state of matter, and the types of bonds they form.

While it is true that an atom is also considered the basic unit of matter, focusing on it as the smallest unit of an element provides a clearer context for its importance in chemistry. Atoms combine to form molecules and compounds, playing a central role in all chemical reactions and processes. Understanding that an atom embodies the essence of an element enhances our grasp of elemental identity and behavior, making it vital for studies in chemistry.