* If you're asking about the number of different types of elements in an atom: There's only one type of element in an atom. An atom is the smallest unit of a chemical element.

* If you're asking about the number of subatomic particles in an atom: This varies depending on the specific atom. There are three main subatomic particles:

* Protons: Positively charged particles located in the nucleus. The number of protons determines the element.

* Neutrons: Neutral particles also located in the nucleus. The number of neutrons can vary within an element, leading to isotopes.

* Electrons: Negatively charged particles that orbit the nucleus in shells or orbitals. The number of electrons is typically equal to the number of protons in a neutral atom.

So, in short, an atom is made up of one type of element, but the number of subatomic particles within that atom can vary.