HELIUM4
Helium-4
Helium-4 is a non-radioactive isotope of the element 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 identical to an alpha particle, and consists of two protons and two neutrons.The above text is a snippet from Wikipedia: Helium-4
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