valence shell

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July 14, 2026

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The valence shell is the outermost electron shell of an atom. It contains the valence electrons, which are the electrons most weakly attracted to the nucleus. These valence electrons are crucial because they are the ones involved in forming chemical bonds, whether through sharing or transfer. The number of electrons in the valence shell dictates an atom's chemical behavior. For example, elements with a full valence shell, like noble gases, are generally stable and unreactive. The energy required to remove a valence electron, known as ionization energy, is a key factor in an atom's ability to form bonds.123456

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chemical bonding
Discovery of the electron
This shell is called the valence shell. The most important feature of the valence shell is that for the noble gases it is complete (in the sense explained below) with its full complement of electrons (i.e., eight, excepting the case of helium). Thus, the formation of chemical bonds appears to…
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This shell is called the valence shell. The most important feature of the valence shell is that for the noble gases it is complete (in the sense explained below) with its full complement of electrons (i.e., eight, excepting the case of helium). Thus, the formation of chemical bonds appears to…
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chemical bonding
Molecular orbitals of H2 and He2
…general, the orbitals in the valence shells of each atom are considered first (not, initially, the electrons those orbitals contain). Then the sets of these orbitals that have the same symmetry with respect to the internuclear axis are selected. (This point is illustrated below.) Bonding and antibonding combinations of each…
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…general, the orbitals in the valence shells of each atom are considered first (not, initially, the electrons those orbitals contain). Then the sets of these orbitals that have the same symmetry with respect to the internuclear axis are selected. (This point is illustrated below.) Bonding and antibonding combinations of each…
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periodic table
Periodicity of properties of the elements
…held in the outermost (valence) shell, to another element with greater electron affinity, thus producing the stable singly charged positive ions. Similarly the alkaline-earth metals can form doubly charged positive ions with the noble-gas electronic configuration by losing the two loosely held electrons of the valence shell; the positive…
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…held in the outermost (valence) shell, to another element with greater electron affinity, thus producing the stable singly charged positive ions. Similarly the alkaline-earth metals can form doubly charged positive ions with the noble-gas electronic configuration by losing the two loosely held electrons of the valence shell; the positive…
Read More