Effective nuclear charge

The effective nuclear charge (often symbolized as Z e f f {displaystyle Z_{mathrm {eff} }} or Z ∗ {displaystyle Z^{ast }} ) is the net positive charge experienced by an electron in a polyelectronic atom. The term 'effective' is used because the shielding effect of negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge of the nucleus due to the repelling effect of inner-layer electrons. The effective nuclear charge experienced by the electron is also called the core charge. It is possible to determine the strength of the nuclear charge by the oxidation number of the atom. The effective nuclear charge (often symbolized as Z e f f {displaystyle Z_{mathrm {eff} }} or Z ∗ {displaystyle Z^{ast }} ) is the net positive charge experienced by an electron in a polyelectronic atom. The term 'effective' is used because the shielding effect of negatively charged electrons prevents higher orbital electrons from experiencing the full nuclear charge of the nucleus due to the repelling effect of inner-layer electrons. The effective nuclear charge experienced by the electron is also called the core charge. It is possible to determine the strength of the nuclear charge by the oxidation number of the atom. In an atom with one electron, that electron experiences the full charge of the positive nucleus. In this case, the effective nuclear charge can be calculated from Coulomb's law. However, in an atom with many electrons, the outer electrons are simultaneously attracted to the positive nucleus and repelled by the negatively charged electrons. The effective nuclear charge on such an electron is given by the following equation: