SOLVED: A helium nucleus has two protons and two neutrons. How many electrons would it take to equal the mass of a helium nucleus? | Numerade

Helium (He) - Physical & Chemical Properties, Uses, Isotopes

Unstable helium adds a limit on the ongoing saga of the proton’s size

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16 Uses of Helium That One Must Know - Techiescientist

The world's helium supplies are running dangerously low – Here's why

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