Question

if all of the atoms in a molecule of a substance are alike, then the substance is a/an ______. answer input: spelling counts but capitalization doesn’t

Explanation:

In chemistry (a subfield of Natural Science), an element is a substance whose molecules (or atoms, in the case of monatomic elements) are made up of only one type of atom. If all atoms in a molecule of a substance are alike, that substance is an element. For example, a molecule of oxygen gas ($O_2$) has two oxygen atoms, and oxygen is an element. Compounds have molecules with different types of atoms, so this fits the definition of an element.

Answer:

element