What is the number of protons in the nucleus of an atom equivalent to? number of neutrons atomic number mass number atomic weight

atomic number

Explanation:

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

Atomic number = Number of electrons = Number of protons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

Atomic weight is the weight of an atom. It is equal to the number of protons and neutrons, with a little extra added by the electrons.

Thus the number of protons in the nucleus of an atom equivalent to atomic number

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