How to determine the charge of the nucleus of an atom, the number of protons in the nucleus, the number of neutrons

How to determine the charge of the nucleus of an atom, the number of protons in the nucleus, the number of neutrons, the mass number of an element?

The atomic nuclear charge is indicated by the ordinal number of the chemical element in the table of D.I. Mendeleev.
The number of protons in the nucleus of an atom is equal to the ordinal number of a chemical element in the table of D.I. Mendeleev.
The number of neutrons in an atom is found by the formula N = A – Z, where A is the mass number, Z is the ordinal number of a chemical element in the D I. Mendeleev table.
The mass number of an atom is approximately equal to its relative atomic mass.

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