What is the basic unit of matter?

• A. Molecule
• B. Atom
• C. Element
• D. Ion

Answer: (B)

Matter is made of atoms, the smallest unit that still has the properties of a particular element. Atoms have a nucleus of protons and neutrons with electrons moving around it, and they can bond to form molecules, which are the building blocks of most substances. An element is defined by the type of atom it contains, while a molecule is a group of atoms bonded together. An ion is simply an atom or molecule with a net electric charge. Because the fundamental building block of any element is the atom, atom is the correct basic unit of matter.