enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    An atom with a closed shell of valence electrons (corresponding to a noble gas configuration) tends to be chemically inert. Atoms with one or two valence electrons more than a closed shell are highly reactive due to the relatively low energy to remove the extra valence electrons to form a positive ion. An atom with one or two electrons fewer ...

  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. Energy level - Wikipedia

    en.wikipedia.org/wiki/Energy_level

    Energy level transitions can also be nonradiative, meaning emission or absorption of a photon is not involved. If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the ground state.

  5. Electronic band structure - Wikipedia

    en.wikipedia.org/wiki/Electronic_band_structure

    For this reason, the adjacent levels are very closely spaced in energy (of the order of 10 −22 eV), [4] [5] [6] and can be considered to form a continuum, an energy band. This formation of bands is mostly a feature of the outermost electrons (valence electrons) in the atom, which are the ones involved in chemical bonding and electrical ...

  6. Electron shell - Wikipedia

    en.wikipedia.org/wiki/Electron_shell

    Although it is sometimes stated that all the electrons in a shell have the same energy, this is an approximation. However, the electrons in one subshell do have exactly the same level of energy, with later subshells having more energy per electron than earlier ones. This effect is great enough that the energy ranges associated with shells can ...

  7. Band gap - Wikipedia

    en.wikipedia.org/wiki/Band_gap

    However, in order for a valence band electron to be promoted to the conduction band, it requires a specific minimum amount of energy for the transition. This required energy is an intrinsic characteristic of the solid material. Electrons can gain enough energy to jump to the conduction band by absorbing either a phonon (heat) or a photon (light).

  8. Octet rule - Wikipedia

    en.wikipedia.org/wiki/Octet_rule

    The quantum theory of the atom explains the eight electrons as a closed shell with an s 2 p 6 electron configuration. A closed-shell configuration is one in which low-lying energy levels are full and higher energy levels are empty. For example, the neon atom ground state has a full n = 2 shell (2s 2 2p 6) and an empty n = 3 shell. According to ...

  9. Carrier generation and recombination - Wikipedia

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

    At absolute zero temperature, all of the electrons have energy below the Fermi level; but at non-zero temperatures the energy levels are filled following a Fermi-Dirac distribution. In undoped semiconductors the Fermi level lies in the middle of a forbidden band or band gap between two allowed bands called the valence band and the conduction ...