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Helium is composed of two electrons bound by the electromagnetic force to a nucleus containing two protons along with two neutrons, depending on the isotope, held together by the strong force. Unlike for hydrogen, a closed-form solution to the Schrödinger equation for the helium atom has not been found.
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.
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 ...
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 ...
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.
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.
In hydrogen, there is only one electron, which must go in the lowest-energy orbital 1s. This electron configuration is written 1s 1, where the superscript indicates the number of electrons in the subshell. Helium adds a second electron, which also goes into 1s, completely filling the first shell and giving the configuration 1s 2. [39] [58] [i]
To do this, the nearest noble gas that precedes the element in question is written first, and then the electron configuration is continued from that point forward. For example, the electron notation of phosphorus is 1s 2 2s 2 2p 6 3s 2 3p 3 , while the noble gas notation is [Ne] 3s 2 3p 3 .