Which of the following best describes the difference between an atom and a molecule?

• A. A molecule is a single particle of an element, while an atom is a group of atoms bonded together.
• B. An atom is always larger than a molecule.
• C. Atoms can only exist as part of molecules.
• D. An atom is a single particle of an element, while a molecule is a group of two or more atoms chemically bonded together.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the definition of an atom. An atom is the smallest unit of an element that retains the chemical properties of that element. It consists of protons, neutrons, and electrons.
2. Step 2: Understand the definition of a molecule. A molecule is formed when two or more atoms chemically bond together. These atoms can be of the same element or different elements.
3. Step 3: Compare the two definitions. An atom is a single particle, while a molecule is a collection of atoms bonded together.
4. Step 4: Recognize that molecules can be made of atoms from the same element (like O\_2) or different elements (like H\_2O), but atoms themselves are individual units.
5. Step 5: Conclude that the best description is: 'An atom is a single particle of an element, while a molecule is a group of two or more atoms chemically bonded together.'