Which statement correctly describes how isotopes of an element are similar and how they are different?

• A. Isotopes have the same number of protons and neutrons.
• B. Isotopes have the same number of protons but different numbers of neutrons.
• C. Isotopes have different numbers of protons but the same number of neutrons.
• D. Isotopes have different numbers of electrons but the same number of protons.

Answer: (B)

Verified step by step guidance

1. Recall that isotopes are variants of the same chemical element, meaning they must have the same number of protons because the number of protons defines the element.
2. Understand that the difference between isotopes lies in the number of neutrons in the nucleus, which affects the atomic mass but not the chemical properties significantly.
3. Recognize that the number of electrons in a neutral atom equals the number of protons, so isotopes of the same element typically have the same number of electrons unless they are ions.
4. Evaluate each statement by comparing it to these facts: isotopes have the same number of protons, different numbers of neutrons, and usually the same number of electrons if neutral.
5. Conclude that the correct description is: isotopes have the same number of protons but different numbers of neutrons.