Correct option is A
The correct answer is (A) Number of Neutrons.
- Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.
- Since the atomic number (which represents the number of protons) remains the same, isotopes belong to the same element but have different atomic masses.
- For example:
- Carbon-12 and Carbon-14 are both isotopes of carbon. They each have 6 protons, but Carbon-12 has 6 neutrons, while Carbon-14 has 8 neutrons.
- Uranium-235 and Uranium-238 are isotopes of uranium, differing in their neutron count.
