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  2. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    Similar to a core electron, a valence electron has the ability to absorb or release energy in the form of a photon. An energy gain can trigger the electron to move (jump) to an outer shell; this is known as atomic excitation. Or the electron can even break free from its associated atom's shell; this is ionization to form a positive ion. When an ...

  3. Valence and conduction bands - Wikipedia

    en.wikipedia.org/wiki/Valence_and_conduction_bands

    In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level, and thus determine the electrical conductivity of the solid. In nonmetals, the valence band is the highest range of electron energies in which electrons are normally present at absolute zero temperature, while the conduction band is the lowest range of vacant electronic states.

  4. 18-electron rule - Wikipedia

    en.wikipedia.org/wiki/18-electron_rule

    Compounds that obey the 18-electron rule are typically "exchange inert". Examples include [Co(NH 3) 6]Cl 3, Mo(CO) 6, and [Fe(CN) 6] 4−.In such cases, in general ligand exchange occurs via dissociative substitution mechanisms, wherein the rate of reaction is determined by the rate of dissociation of a ligand.

  5. Carrier generation and recombination - Wikipedia

    en.wikipedia.org/wiki/Carrier_generation_and...

    The electron–hole pair is the fundamental unit of generation and recombination in inorganic semiconductors, corresponding to an electron transitioning between the valence band and the conduction band where generation of an electron is a transition from the valence band to the conduction band and recombination leads to a reverse transition.

  6. Hypervalent molecule - Wikipedia

    en.wikipedia.org/wiki/Hypervalent_molecule

    In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells.

  7. Electron configurations of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Electron_configurations_of...

    The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below. As an approximate rule, electron configurations are given by the Aufbau principle and the Madelung rule.

  8. Cerium - Wikipedia

    en.wikipedia.org/wiki/Cerium

    Its 58 electrons are arranged in the configuration [Xe]4f 1 5d 1 6s 2, of which the four outer electrons are valence electrons. [10] The 4f, 5d, and 6s energy levels are very close to each other, and the transfer of one electron to the 5d shell is due to strong interelectronic repulsion in the compact 4f shell.

  9. Polyhedral skeletal electron pair theory - Wikipedia

    en.wikipedia.org/wiki/Polyhedral_skeletal...

    Electron count: 4 × P = 4 × 5 = 20 It is a 5n structure with n = 4, so it is tetrahedral. Example: P 4 S 3. Electron count 4 × P + 3 × S = 4 × 5 + 3 × 6 = 38 It is a 5n + 3 structure with n = 7. Three vertices are inserted into edges. Example: P 4 O 6. Electron count 4 × P + 6 × O = 4 × 5 + 6 × 6 = 56 It is a 5n + 6 structure with n ...