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Its nucleus is identical to an alpha particle, and consists of two protons and two neutrons. Alpha decay of heavy elements in the Earth's crust is the source of most naturally occurring helium-4 on Earth, produced after the planet cooled and solidified.
The following table shows the atomic nuclei that are isotonic (same neutron number N = 2) and isobaric (same nucleon number A = 4) with Helium-4. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.
Helium - Protons - Neutrons - Electrons - Electron Configuration. Helium has 2 protons and electrons in its structure. The total number of neutrons in the nucleus of an atom is called the neutron number. Typical isotopes of helium are helium-4 and helium-3.
Helium-4 (4 He) 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.
The most widely studied heavy helium isotope is 8 He. 8 He and 6 He are thought to consist of a normal 4 He nucleus surrounded by a neutron "halo" (of two neutrons in 6 He and four neutrons in 8 He). Halo nuclei have become an area of intense research. Isotopes up to 10 He, with two protons and eight neutrons, have been confirmed.
Helium-4 is a non- radioactive and light isotope of helium. It is by far the most abundant of the two naturally-occurring isotopes of helium, making up about 99.99986% of the helium on earth. Its nucleus is a boson and an alpha particle, having two protons and two neutrons.
alpha particle. …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. Discovered and named (1899) by Ernest Rutherford, alpha.
