chemistry terms

What is an atom?

The smallest unit of matter that retains an element's chemical identity.

Define a molecule.

A group of two or more atoms held together by chemical bonds.

What is a chemical reaction?

A process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in its physical form or a nuclear reaction.

What is an element?

A pure substance consisting only of atoms that all have the same numbers of protons in their atomic nuclei.

How is a covalent bond formed?

A covalent bond is formed when atoms share electrons to achieve a stable electron configuration.