Question

why all the mass of an atom is concentrated in the nucleus?
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Answer 1

Explanation:

All the mass of an atom is concentrated in the nucleus because atom contains three subatomic particles like electron, proton and neutron. ... Atomic mass number is a whole number because it is the sum of numbers of protons and numbers of neutrons present in an atom.

Answer 2

Answer:

Hope this helps you

Explanation:

All the mass of an atom is concentrated in the nucleus because atom contains three subatomic particles like electron, proton and neutron. Atomic mass number is a whole number because it is the sum of numbers of protons and numbers of neutrons present in an atom.