Say one of the electrons in the helium atom is excited to the 2s state.

To pull these helium atoms apart, this energy must be put back.

Thus the "molecule" is represented by a single helium atom.

Only about one out of every 650,000 C were found with a helium atom.

Therefore the information carried out in the scattered helium atom comes solely from the very surface of the sample.

The symbols inside may be four hydrogen atoms next to a helium atom.

A helium atom weighs less than the four original hydrogen atoms.

This is followed by the ionization of the hydrogen and helium atoms.

The two orbiting electrons of the helium atom form a shell.

Their transition to ground state takes place by collision with cold helium atoms.