Question

7 why are sodium - 23 and sodium - 24 different isotopes? a different number of electrons b different atomic numbers c one is chemically reactive, the other is not d different mass numbers

Explanation:

Isotopes of an element have the same atomic number (same number of protons) but different mass numbers due to different numbers of neutrons. Sodium - 23 and sodium - 24 are isotopes of sodium, so they have different mass numbers.

Answer:

D. Different mass numbers