Which of the following is the smallest representative particle of an element?

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

Answer: (D)

Verified step by step guidance

1. Understand the question: It asks for the smallest representative particle of an element. This means the smallest unit that still retains the properties of that element.
2. Review the options: Proton, Molecule, Ion, and Atom. Consider what each represents in terms of size and composition.
3. Recall definitions: A proton is a subatomic particle found in the nucleus of an atom, but alone it does not represent the element itself. A molecule is a group of atoms bonded together, often representing compounds or elements in molecular form. An ion is an atom or molecule with a net electric charge due to loss or gain of electrons. An atom is the smallest unit of an element that retains the chemical properties of that element.
4. Compare the options: Since a proton is only a part of an atom, and molecules and ions are larger or charged forms, the atom is the smallest particle that still represents the element's identity.
5. Conclude that the atom is the correct answer because it is the smallest particle that maintains the chemical properties of the element.