Which statement correctly describes how isotopes of a given element differ and how they are similar?

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

Answer: (C)

Verified step by step guidance

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