Element

An element is a single type of atom as defined by its atomic number, which is the number of protons in its nucleus. In contrast, a single element may have varying mass numbers, relating to the number of neutrons in its nucleus.

The element hydrogen has only one proton whereas the element uranium has 92, and there are elements with even more protons than that. However, uranium is the largest naturally occurring element in nature.

All known elements are listed on the periodic table, with the ones with more protons than uranium produced in a laboratory. Joining atoms of the same or different elements produces chemical compounds. The elements and their compounds make up all matter on the earth and quite possibly all matter outside of the earth as well.

See also

• Native element
• Periodic table of the elements