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  2. Helium compounds - Wikipedia

    en.wikipedia.org/wiki/Helium_compounds

    Ionised helium (He +), also known as He II, is a very high energy material able to extract an electron from any other atom. He + has an electron configuration like hydrogen, so as well as being ionic it can form covalent bonds. Excimers do not last for long, as the molecule containing the higher energy level helium atom can rapidly decay back ...

  3. Helium - Wikipedia

    en.wikipedia.org/wiki/Helium

    Helium. hexagonal close-packed (hcp) Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table.

  4. Helium atom - Wikipedia

    en.wikipedia.org/wiki/Helium_atom

    The potential is a Coulomb interaction, so the corresponding individual electron energies are given by = = and the corresponding spatial wave function is given by (,) = (+) If Z e was 1.70, that would make the expression above for the ground state energy agree with the experimental value E 0 = −2.903 a.u. of the ground state energy of helium.

  5. Electron configuration - Wikipedia

    en.wikipedia.org/wiki/Electron_configuration

    Electron configuration. In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. [1] For example, the electron configuration of the neon atom is 1s2 2s2 2p6, meaning that the 1s, 2s, and 2p subshells are occupied by ...

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

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

    This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. For phosphorus (element 15) as an example, the concise form is [Ne] 3s 2 3p 3.

  7. Periodic table (electron configurations) - Wikipedia

    en.wikipedia.org/wiki/Periodic_table_(electron...

    Grayed out electron numbers indicate subshells filled to their maximum. Bracketed noble gas symbols on the left represent inner configurations that are the same in each period. Written out, these are: He, 2, helium : 1s 2. Ne, 10, neon : 1s 2 2s 2 2p 6. Ar, 18, argon : 1s 2 2s 2 2p 6 3s 2 3p 6.

  8. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    As a general rule, a main-group element (except hydrogen or helium) tends to react to form a s 2 p 6 electron configuration. This tendency is called the octet rule, because each bonded atom has 8 valence electrons including shared electrons. Similarly, a transition metal tends to react to form a d 10 s 2 p 6 electron configuration.

  9. Pauli exclusion principle - Wikipedia

    en.wikipedia.org/wiki/Pauli_exclusion_principle

    An example is the neutral helium atom (He), which has two bound electrons, both of which can occupy the lowest-energy states by acquiring opposite spin; as spin is part of the quantum state of the electron, the two electrons are in different quantum states and do not violate the Pauli principle.