## Coulomb's Law, repulsion, electrons and shells

Created April 2020, Offline version here
Video by Paul Andersen. Visit his website: Bozeman Science.

Electron configuration involves the distribution of around the nucleus. This distribution can be found in atoms or ions.
is the amount of energy used to remove an electron from an atom. This is amount of energy is experimentally determined in the gas phase. If we have a close look at the electrons in an atom, we will see electrons on the inside and electrons on the outside of the atom. The electrons on the inside are called electrons. We can say that the inside of an atom can be filled with electrons when all the orbitals on the inside are filled with electrons. These inner electrons then the electrons on the outside from the power of the positive nucleus. When the core electrons shield the valence electrons, this means that the valence electrons will not experience the complete of the nucleus as the case would be without the presence of core electrons. The shielding effect of the core electrons on the valence electrons will therefore cause the force between the valence electrons and the nucleus to be different than what is expected. The valence electrons will experience a attraction by the nucleus. The equation that represents quantifies the electrostatic force between two objects whenever the objects act as point charges. We can therefore use this equation to calculate the electrostatic force between a valence electron and a proton in the nucleus of an atom. According to Coulomb’s law, the ionization energy is direct proportional to the size of charges involved and indirectly proportional to the distance between the two charges. If the distance between the relevant charges increases, then the ionization energy will . Helium has a higher ionization energy than hydrogen. This can be explained by the attraction between the more positive nucleus on the valence electrons. The valence electron of lithium lies in the second . This electron is therefore shielded from the attraction force of nucleus by the two core electrons. The shielding effect in lithium will cause the valence electron to experience a weaker attraction from the positively charged nucleus than expected. The ionization energy of lithium will therefore be that for helium. According to the ionization chart there is a general increase in the ionization energy from left to right in a period. In a specific group there is generally in the ionization energy from top to bottom. Electrons are housed in orbitals. Each orbital can hold electrons. Lithium has three electrons. The valence electron in lithium lies in the orbital. A shell contains one or more subshells and each subshell contains orbitals. There is one subshell in the first shell and subshells in the second shell. The ionization energy of oxygen is unexpectedly lower than that for nitrogen. This phenomenon is due to the between electrons in the same orbital. Two of the valence electrons of nitrogen will reside in p orbitals. These two electrons will be placed in p orbital(s). Subshells consist of orbitals. The s subshell has one s orbital in it, the p subshell has three p orbitals in it and the d subshell has orbitals in it.
When filling orbitals with electrons, we will start filling the 3p orbitals as soon as the 3s orbitals are full. When the 3p orbitals are full, we will start filling the orbitals. The 4f orbitals will be filled with electrons as soon as the 6s orbital is full. This will be followed by filling the orbitals. There is one orbital in the first shell and four orbitals in the second shell. There are orbitals in the third shell. There can be a maximum of two electrons in the first shell. There can be a maximum of electrons in the first three shells.
The spdf electron configuration can sometimes be very long to write out and in such cases we therefore make use of an abbreviated version. The abbreviated electron configuration for calcium is . The electron configuration of potassium is [Ar]4s1. The electron configuration of titanium is .