helium-4
Sign in to save300px|thumb|right|alt=Picture of a diffuse gray sphere with grayscale density decreasing from the center. Length scale about 1 Angstrom. An inset outlines the structure of the core, with two red and two blue atoms at the length scale of 1 femtometer.|The helium atom. Depicted are the atomic nucleus|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.]]
Key facts
- Isotope.symbol
- He
- Isotope.mass_number
- 4
- Isotope.mass
- 4.002603254
- Isotope.binding_energy
- 28295.7
- Isotope.num_neutrons
- 2
- Isotope.num_protons
- 2
- Isotope.abundance
- 99.999863% (atmosphere)
- Isotope.halflife
- stable
- Isotope.image
- Helium discharge tube.jpg
- Isotope.parent_decay
- Alpha decay
- Isotope.spin
- 0
via Wikipedia infobox
Article
7 sectionsContents
- Occurrence
- Properties
- The helium-4 atom
- Stability of the <sup>4</sup>He nucleus and electron shell
- See also
- References
- External links
300px|thumb|right|alt=Picture of a diffuse gray sphere with grayscale density decreasing from the center. Length scale about 1 Angstrom. An inset outlines the structure of the core, with two red and two blue atoms at the length scale of 1 femtometer.|The helium atom. Depicted are the atomic nucleus|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 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up virtually all the helium on Earth. Its nucleus consists of two protons and two neutrons and is identical to an alpha particle.