This isotope is found at a ratio of about one per 2,500 helium-4 ions, the latter being the common version of helium.

The atom is neutral as it has two positive protons and two negative electrons. A helium atom that has lost or gained an electron is an ion. The ion has two positive protons but one electron so it ...

If an atom has 2 protons, that’s an atom of the element helium. If it has 7 protons, that’s nitrogen. But the logic of the periodic table also relies upon the number and organisation of electr ...

In this configuration every atom has on the average four nearest neighbours ... For T T0 the specific heat is given by (4) Though actually the X-point of helium resembles rather a phase transition ...