What is the smallest unit of an element?

The smallest unit of an element is an atom. Atoms are the fundamental building blocks of matter and retain the properties of the element they represent. Each atom consists of a nucleus, containing protons and neutrons, and is surrounded by electrons that orbit the nucleus.

Molecules, on the other hand, are formed when two or more atoms bond together. This means that molecules can consist of one or more atoms, making them larger than a single atom.

Electrons are subatomic particles that carry a negative charge, but they are not elements themselves; they are components of atoms.

Nucleotides are the building blocks of nucleic acids like DNA and RNA, meaning they are larger structures that consist of multiple components, making them further removed from being fundamental units of an element.

Thus, the correct answer highlights the role of atoms as the defining unit of each element in the periodic table.