Isotopes share protons but differ in neutrons

Steps:

• Recall isotopes are atoms of the same element with identical atomic numbers but different mass numbers.
• Atomic number equals proton count; mass number is protons plus neutrons.
• Bromine isotopes (e.g., Br-79, Br-81) have 35 protons each but varying neutrons.
• Evaluate options against this definition to identify the accurate statement.

Why C is correct:

• Isotopes have the same number of protons (atomic number 35 for bromine), determining electron configuration and thus identical chemical properties, per the periodic table's structure.

Why the others are wrong:

• A: Contradictory—states same and different electrons; isotopes have same electrons in neutral atoms.
• B: Incorrect—bromine isotopes differ in neutrons (e.g., 44 vs. 46), not the same.
• D: False—isotopes have different physical properties due to varying masses (e.g., density, boiling point).

Final answer: C