Which term best describes a group of atoms joined together in a particular way?

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

Answer: (A)

Verified step by step guidance

1. Understand the definitions of each term: An \textbf{ion} is an atom or group of atoms with a net electric charge due to the loss or gain of electrons.
2. An \textbf{isotope} refers to atoms of the same element that have different numbers of neutrons, thus differing in mass but not in chemical properties.
3. An \textbf{element} is a pure substance consisting of only one type of atom, characterized by its atomic number.
4. A \textbf{molecule} is a group of two or more atoms chemically bonded together in a specific arrangement.
5. Since the question asks for a term describing a group of atoms joined together in a particular way, the best choice is \textbf{molecule}.