Helium is notoriously hard to contain because, like hydrogen, it is a tiny little atom even by atomic standards. It also expands about 750 times when it turns into a gas, according to the post’s ...

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 ...

A helium atom has two electrons in an energy level outside the nucleus. The atom is neutral as it has two positive protons and two negative electrons. A helium atom that has lost or gained an ...

For example, a helium atom has an atomic mass of 4, but an atomic number (or positive charge) of 2. Since electrons have almost no mass, it seemed that something besides the protons in the nucleus ...

Every space launch has risk tolerances, and NASA has judged this one to be in bounds. Helium is a tiny atom that is difficult to fully contain—even the highly successful SpaceX Dragon has ...