Shell models of the atom

Sir Ernest Rutherford (1871-1937 Nobel Prize for chemistry 1908, which as a physicist he puzzled over) was a brilliant experimentalist endowed with an equal genius of being able to interpret the results. He recognized three types of radiation (alpha, beta, and gamma). He used scattering experiments with alpha radiation, which consists of helium nuclei, to prove that the atom is almost empty. The diameter of the atomic nucleus is about 10 000 times smaller than the atom itself. Furthermore, he proved that atoms are not indivisible and that in addition to protons, there must also be neutrons present in their nucleus. With Niels Bohr he developed the core-shell model of the atom. 

Electron-dot structure A shorthand notation of the shell model of the atom in which valence electrons are shown around an atomic symbol. 

This approach yields the shell model of the atom in which, under the restrictions of the Pauli principle and according to the aufbau principle, the electrons i are placed in the spin-orbitals (r, ms). For example, the shell structure of the magnesium atom is sketched schematically in Fig. 1.1. 

The Hartree orbitals are the foundation of the quantum explanation of atomic structure. They justify the shell model of the atom, they explain the structure of the periodic table, and they provide the starting point for the quantum explanation of chemical bond formation in the following chapter. 

The Hartree orbitals and their electron configurations justify the shell model of the atom that is, the electrons are grouped into shells of 2, 8, or 18 electrons... 

Given the shell model of the atom, suggest a possible reason that Lewis proposed a maximum of two electrons for hydrogen and a maximum of eight for carbon, nitrogen, oxygen, and fluorine atoms ... 

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