Helium atom

A helium atom is an atom of the chemical element helium. 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. However, various approximations, such as the Hartree–Fock method, can be used to estimate the ground state energy and wavefunction of the atom. Historically, the first such helium spectrum calculation was done by Albrecht Unsöld in 1927. Its success was considered to be one of the earliest signs of validity of Schrödinger's wave mechanics.

This article is about the physics of atomic helium. For other properties of helium, see Helium.
Helium atom

Helium-4
Names
Systematic IUPAC name
Helium
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
EC Number
  • 231-168-5
16294
KEGG
MeSH Helium
RTECS number
  • MH6520000
UNII
UN number 1046
  • InChI=1S/He Y
    Key: SWQJXJOGLNCZEY-UHFFFAOYSA-N Y
  • [He]
Properties
He
Molar mass 4.002602 g·mol−1
Appearance Colourless gas
Boiling point −269 °C (−452.20 °F; 4.15 K)
Thermochemistry
126.151-126.155 J K−1 mol−1
Pharmacology
V03AN03 (WHO)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references
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