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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 .
The helium atom, the smallest of atoms, has a nucleus (pink) consisting of two protons (red) and two neutrons (purple). The fuzzy cloud is the electron probability cloud, with darker regions of the cloud indicating where the electron most likely is.
The helium atom. Depicted are the ... Such computational chemistry methods have been used to create a quantum mechanical picture of helium electron binding which is ...
The helium atom. Depicted are the nucleus (pink) and the electron cloud distribution (black). The nucleus (upper right) in helium-4 is in reality spherically symmetric and closely resembles the electron cloud, although for more complicated nuclei this is not always the case. Helium-4 (4 He) is a stable isotope of the element helium.
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Helium-3 (3 He [1] [2] see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and protium (ordinary hydrogen) are the only stable nuclides with more protons than neutrons. It was discovered in 1939.
The helium atom is small with the radius of the outer electron shell at 0.29 Å. [2] Helium is a very hard atom with a Pearson hardness of 12.3 eV. [3] It has the lowest polarizability of any kind of atom, however, very weak van der Waals forces exist between helium and other atoms.
A helium atom image of a fly's eye SHeM Contrast Mechanism Tree. The atomic beam is formed through a supersonic expansion, which is a standard technique used in helium atom scattering. The centreline of the gas is selected by a skimmer to form an atom beam with a narrow velocity distribution.