The number of neutrons in dipositive zinc ion (Zn2+) with mass number 70 is:

Correct option is C

The correct answer is: (c) 40
Explanation: Given: • Atomic number of Zn = 30 → Protons = 30 • Mass number = 70 • Neutrons = Mass number – Atomic number = 70 – 30 = 40
Zn²⁺ still has 30 protons and 40 neutrons.
Information Booster: • Electrons lost/gained do not affect the number of neutrons. • Neutron count = mass number – proton number.