Helium-4 - Wikipedia
Helium-4 (4He) 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 about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consists of two protons and two neutrons.
Helium-4 - isotopic data and properties - ChemLin
Properties and data of the isotope 4 He. Contents. General Data. Parent Nuclides. Isotones und Isobares. Literature. See also: list of Helium isotopes.
Helium-4 | chemical isotope | Britannica - Encyclopedia Britannica
helium-4. atomic nucleus. alpha particle, positively charged particle, identical to the nucleus of the helium -4 atom, spontaneously emitted by some radioactive substances, consisting of two protons and two neutrons bound together, thus having a mass of four units and a positive charge of two.
Isotopes of helium - Wikipedia
Helium (2 He) (standard atomic weight: 4.002 602 (2)) has nine known isotopes, but only helium-3 (3 He) and helium-4 (4 He) are stable. [4] All radioisotopes are short-lived; the longest-lived is 6 He with half-life 806.92(24) milliseconds .
Superfluidity: the mysterious quantum effect that became a …
2024年2月14日 · The strange properties of superfluid helium-4 (also known as liquid helium II) arise because of the quantum rules governing the symmetry of the wave functions of helium atoms. Electrons, which are fermions, cannot occupy the same quantum state, but the same is not true for helium-4 atoms.
Atmospheric Helium Levels Are Rising as a Byproduct of Fossil Fuels
2022年5月11日 · The researchers focused specifically on helium-4, the isotope that’s released in the greatest volumes during fossil fuel production. They found that helium-4 is, indeed, rising in the...
Helium-4 - Simple English Wikipedia, the free encyclopedia
Helium-4 (also written 4 He) is an isotope of helium. It is the most common isotope of helium in the universe. Out of all the helium on the Earth, 99.99986% is helium-4. The nucleus (the center) of a helium-4 atom is also known as the alpha particle.
Helium-4 - Vocab, Definition, and Must Know Facts - Fiveable
Helium-4 is a stable isotope of helium with two protons and two neutrons in its nucleus, making it the most common helium isotope found in the universe. It is a key product of nuclear fusion reactions, particularly in stars, where it is generated from the fusion of hydrogen atoms.
Helium nucleus measured with record precision - Nature
2021年1月27日 · The nucleus of its most common isotope, helium-4, consists of two protons and two neutrons and is called the α-particle. This particle is more compact than other light nuclei — for instance, it...
Eighty years of superfluidity - Nature
15 January 2018. Eighty years of superfluidity. In 1938, two studies demonstrated that liquid helium-4 flows without friction or viscosity at temperatures close to absolute zero. The finding...