Page "Plum pudding model" Paragraph 4

to imply a very small nucleus of the atom containing a very high positive charge ( in the case of gold, enough to balance about 100 electrons ), thus leading to the Rutherford model of the atom.

Although gold has an atomic number of 79, immediately after Rutherford's paper appeared in 1911 Antonius Van den Broek made the intuitive suggestion that atomic number is nuclear charge.

The matter required experiment to decide.

Henry Moseley's work showed experimentally in 1913 ( see Moseley's law ) that the effective nuclear charge was very close to the atomic number ( Moseley found only one unit difference ), and Moseley referenced only the papers of Van den Broek and Rutherford.

This work culminated in the solar-system-like ( but quantum-limited ) Bohr model of the atom in the same year, in which a nucleus containing an atomic number of positive charge is surrounded by an equal number of electrons in orbital shells.

Bohr had also inspired Moseley's work.