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Question
Give scientific reason.
All the mass of an atom is concentrated in the nucleus.
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Solution
All the mass of an atom is concentrated in the nucleus because the atom contains three subatomic particles like electron, proton and neutron. Out of which, the nucleus present at the centre of an atom contains two subatomic particles that are protons and neutrons, and the mass of the nucleus is the sum of the mass of protons and neutrons located at the centre of an atom.
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