Which of the following statements correctly describes isotopes of an atom?

• A. Isotopes have different numbers of protons and the same number of neutrons.
• B. Isotopes have the same number of protons but different numbers of neutrons.
• C. Isotopes have the same mass number but different atomic numbers.
• D. Isotopes have different chemical properties because they have different numbers of electrons.

Answer: (B)

Verified step by step guidance

1. Recall the definition of isotopes: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
2. Understand that the number of protons defines the element (atomic number), so isotopes must have the same atomic number.
3. Recognize that the difference in the number of neutrons causes isotopes to have different mass numbers (sum of protons and neutrons).
4. Note that isotopes generally have very similar chemical properties because chemical behavior is primarily determined by the number of electrons, which is equal to the number of protons in a neutral atom.
5. Evaluate each statement based on these points to identify the correct description of isotopes.