Question

The mass number of a nucleus is
1. Always less than its atomic number
2. Always more than its atomic number
3. Sometimes more than and sometimes equal to its atomic number
4. None of the above

Answer 1

Hi there,

4.None of the above.

None of these are correct.

Answer 2

the correct option is 3. sometimes more than and sometimes equal to it's atomic number.

basically mass number is greater than it's atomic number as it's the sum of protons and neutrons present in the nucleus if the atom whereas atomic number is the no. of electrons and no. of electrons = no. of protons.

so clearly we can see, mass number will be greater than the atomic number.

but sometimes it's also equal. for example - hydrogen isotope PROTIUM. it has a single electron and proton with no neutrons. hence, their atomic number and mass number is also equal.

so the correct option is 3.