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The mass number of a nucleus is
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- always less than its atomic number
- always more than its atomic number
- always equal to its atomic number
- sometimes more and somtimes equal to its atomic number
- always less than its atomic number
Correct Option: D
Mass number = protons or mass of electron (atomic number) + neutrons. So it is mostly greater than the atomic number. At best, it can be equal to the atomic number.
