Effective nuclear charge is the net positive charge experienced by an electron in a multi-electron atom, accounting for both the actual nuclear charge and the shielding effect of other electrons. It plays a crucial role in determining atomic properties such as atomic radius, ionization energy, and electron affinity.

Effective Nuclear Charge

Effective nuclear charge

net positive charge

multi-electron atom

actual nuclear charge

The shielding effect refers to the reduction in effective nuclear charge on the electron cloud, due to the repulsion between electrons in different shells. This phenomenon explains why electrons in outer shells are less tightly bound to the nucleus, influencing atomic size, ionization energy, and electron affinity.

shielding effect

atomic properties

Atomic radius is the distance from the nucleus of an atom to the outer boundary of its electron cloud, which determines the size of the atom. It generally decreases across a period due to increased nuclear charge and increases down a group due to the addition of electron shells.

atomic radius

Ionization energy is the amount of energy required to remove an electron from an isolated atom or ion in its gaseous state. It is a fundamental property that reveals the reactivity of elements, with higher ionization energies indicating a stronger hold on electrons and typically less reactivity.

ionization energy

Electron affinity is the energy change that occurs when an electron is added to a neutral atom in the gaseous state, indicating how strongly an atom can attract additional electrons. It generally becomes more exothermic across a period due to increasing nuclear charge and less exothermic down a group due to increased atomic radius and electron shielding.

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