Which of the following is the smallest unit of an element that retains the properties of that element?

• A. Molecule
• B. Proton
• C. Atom
• D. Electron

Answer: (C)

Verified step by step guidance

1. Understand the question: It asks for the smallest unit of an element that retains the properties of that element.
2. Recall the definitions of the options: A molecule is a group of atoms bonded together; a proton is a subatomic particle found in the nucleus; an electron is a subatomic particle orbiting the nucleus; an atom is the smallest unit of an element that retains its chemical properties.
3. Recognize that subatomic particles (protons and electrons) do not retain the chemical properties of the element on their own because they are parts of an atom, not the whole unit.
4. Understand that molecules can be made of atoms from the same or different elements, so they are not necessarily the smallest unit of a single element.
5. Conclude that the atom is the smallest unit of an element that retains all the chemical properties of that element.