Valence Electron

In chemistry, a valence electron is an electron that is associated with an atom, and that can participate in the formation of a chemical bond; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair. The presence of valence electrons can determine the element's chemical properties and whether it may bond with other elements: For a main group element, a valence electron can only be in the outermost electron shell. In a transition metal, a valence electron can also be in an inner shell.

An atom with a closed shell of valence electrons (corresponding to an electron configuration s2p6) tends to be chemically inert. An atom with one or two valence electrons more than a closed shell is highly reactive, because the extra valence electrons are easily removed to form a positive ion. An atom with one or two valence electrons fewer than a closed shell is also highly reactive, because of a tendency either to gain the missing valence electrons (thereby forming a negative ion), or to share valence electrons (thereby forming a covalent bond).

Like an electron in an inner shell, a valence electron has the ability to absorb or release energy in the form of a photon. This gain or loss of energy can trigger an electron to move (jump) to a more outer shell or even break free from its associated atom's valence shell; this is known as atomic excitation. When an electron loses energy (thereby causing photons to be emitted), then it moves to a more inner shell.

Read more about Valence ElectronThe Number of Valence Electrons, Electron Configuration, Chemical Reactions, Electrical Conductivity

Other articles related to "valence, valence electron, valence electrons, electrons, electron":

Multivalent - "Maximum Number of Bonds" Definition
... to arrive at an unambiguous definition of valence ... Hydrogen has only one valence electron and can form only one bond with an atom that has an incomplete outer shell ... Chlorine has seven valence electrons and can form only one bond with an atom that donates a valence electron to complete chlorine's outer shell ...
Valence Electron - Electrical Conductivity
... Valence electrons are also responsible for the electrical conductivity of an element as a result, an element may be classified as a metal, a nonmetals ... occur to the left of the nonmetals, and thus a metal has fewer possible valence electrons than a nonmetal ... However, a valence electron of a metal atom has a small ionization energy, and in the solid state this valence electron is relatively free to leave ...
Group 12 Element - Chemistry - Relationship With The Alkaline Earth Metals
... Although group 12 lies in the d-block of the modern 18-column periodic table, the d electrons of zinc, cadmium, and (almost always) mercury behave as core electrons and do not take part in bonding ... silver, and gold), which also have filled d-subshells in their ground-state electron configuration but behave chemically as transition metals ... the bonding in chromium(II) sulfide (CrS) involves mainly the 3d electrons that in iron(II) sulfide (FeS) involves both the 3d and 4s electrons but that ...