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Question
What is nucleus of an atom? Compare its size with that of the atom. Name its constituents. How is the number of these constituents determined by the atomic number and mass number of the atom?
Solution
The nucleus is a dense, massive, positively charged structure that is tiny in comparison with the rest of the atom and is located in the center of an atom.
The size of a nucleus is 10-5 to 10-4 times that of an atom, or 10,000 to 100,000 times larger.
Constituents of Atom: Protons and neutrons
Atomic mass A = Protons + Neutrons
∴ Number of neutrons= A - Z
Atomic Number Z = Number of protons = Number of electrons
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