Which Elements Exist as Diatomic Molecules?

[Muzzae]

Which elements "travel in pairs"?

This isn't exactly "homework help", just something that's been on my mind for a while. I know that when writing chlorine, oxygen and hydrogen by itself, you need to add a two. Why is this so? And also, what other elements "travel in pairs"?

 

[POSITION_VECTOR]

the halogen and the inert gases "travel in pairs." bromine, iodine...Xe...

 

[Muzzae]

Aha...answer found here. This thread can be closed :)

 

[Cesium]

Consider also:

phosphorous- P4
arsenic- As4
sulfur- S8 and others

 

[Astronuc]

Inert (noble) gases are monatomic.

H, N, O, and halogens F, Cl, Br, I, At form pairs, or diatomic molecules.

Cesium gave forms in which molecules have quadruples or octuples.

 

[matthew77ask]

Question related to this...

Halogen and such gases exists in diatomic - we write Cl2, I2 etc.
But sulphur exist in S8, why we write S in our equations?
then when do we write as element (in S) and when we write in molecule as in Cl2?

thanks