Question

The mass number of a nucleus is

• A. always less than its atomic number
• B. always more than its atomic number
• C. sometimes equal to its atomic number
• D. sometimes more than and sometimes equal to its atomic number

Answer 1

Answer: (D)

sometimes more than and sometimes equal to its atomic number

The mass number of the nucleus is always equal to the sum of protons and neutrons present in the nucleus, which is atomic mass of the nucleus.

The mass of the electron is almost negligible. So, the mass does not get affected by changing the number of electron