The picture shows a close-up of one carbon atom. A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus. The electron and proton are attracted to each other.

It came when the one electron of the hydrogen atom transitioned from the 2P 1/2 energy level to the 2S 1/2 level. (The leftmost number is the principal quantum number, much like the discrete but ...

Like ordinary water—H 2 0—each molecule of heavy water contains two hydrogen atoms and one oxygen atom. The difference, though, lies in the hydrogen atoms. In ordinary water, each hydrogen ...

The typical size of atoms and small molecules is around 1 × 10-10 m (0.1 nm). For example: diameter of a hydrogen atom, H 1.0 × 10-10 m width of a hydrogen molecule, H 2 2.9 × 10-10 m ...