Atoms, molecules, elements and compounds

An element is a pure substance that consists of only one type of atom.

Atoms are made of protons, neutrons, and electrons.

A molecule is a group of two or more atoms bonded together.

A compound is a substance formed when two or more different types of atoms bond together.

Protons are positively charged particles found in the nucleus of an atom.

Neutrons are neutral particles found in the nucleus of an atom.

Electrons are negatively charged particles that orbit the nucleus of an atom.

The atomic number is the number of protons in the nucleus of an atom, which determines the element's identity.

The mass number is the total number of protons and neutrons in an atom's nucleus.

An element consists of only one type of atom, while a compound consists of two or more different types of atoms bonded together.