element!
A substance made up of only one kind of atom is an element, which is a pure substance.
Element
an element or a molecule
This is an isotope of a chemical element.
Elements only contain one kind of atom.
element
hydrogen
Element
atom
An element is made up of one kind of atoms
An element is a substance made of only one kind of atom. Each element has a unique atomic number, which represents the number of protons in its nucleus. Examples of elements include oxygen, gold, and carbon.
Element