chemistry terms

What is chemistry?

Chemistry is the branch of science that deals with the properties, composition, and structure of elements and compounds, how they can change, and the energy that is released or absorbed when they change.

What is an atom?

An atom is the smallest unit of ordinary matter that forms a chemical element. It consists of a nucleus (with protons and neutrons) and electrons orbiting the nucleus.

What is a molecule?

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.

What is an element?

An element is a pure substance consisting only of atoms that all have the same numbers of protons in their atomic nuclei.