Deadliest gas on the world?

[Bridge]

Sorry, I'm a bit unfamiliar with the correct terminology in english...so I might have created some misunderstandings there. (Also I don't have those lower case numbers on my keyboard so I can't write them under the atom symbols as usual ) What I meant was this:

An Oxygen atom is O. Oxygen (the gas) however consists of Oxygen molecules which are O2, because one oxygen molecule consists of two oxygen atoms.
Likewise, a hydrogen atom is H, hydrogen gas consists of hydrogen molecules --> H2.

(While the correct terminology may in fact be dihydrogen and dioxide respectively, my german - english dictionary tells me that the gases are still simply called hydrogen and oxygen.)

The correct formula for the reaction of hydrogen and oxygen to water would therefore be:

2* H2 + O2 = 2* H2O (two hydrogen molecules and one oxygen molecule make two water molecules)

Bitte, ich totally screwed up. But how can H2 and O2 form H2O? Seems to me like an oxygen atom would get lost in the process.