Metal vapors

[Mr Skeptic]

What does a metal vapor look like? Sodium vapor, for example? I'd imagine it would lose it's silvery aspect, but would it have a color?

[vordhosbn]

Well, tin-lead soldering alloys are evaporeted into pretty usual looking white smoke. Or maybe the smoke is tin/lead oxide...

[John Cuthber]

I believe sodium vapour is blue. It absorbs exactly the same yellow light that a sodium lamp emits.

[Horza2002]

I assume that sodium is coloured because heating it past its boiling point also takes it past its first ionisation energy; so gives it its characteristic orange colour. But if thats the case, then wouldn't it be a plasma and not a gas...

[John Cuthber]

I'm fairly sure that it's neutral sodium atoms that give that yellow colour.

[rogerxd45]

most ive seen are white

 

whether that's the oxide or metal vapor i dont know

[Zolar V]

I think i have brought up this type of question before. although my question was whether or not metal could be a gas.

[Horza2002]

Metals can be gases yes...its just that they have such a high boiling point that they are rarely observed in it.

 

After some thought, I didn't mean the first ionisation energy with regards to the sodium gas colour. I actually meant that heating sodium to a gas is enough to excite the electrons to give the characterisitc colour of sodium...not the ionisation energy

[Mr Skeptic]

Good points re the glowing hot gas. I think that you'd need to shine a very bright light on it to get "its color" separated from "its glow". Mercury vapor might be an exception to this.

[John Cuthber]

Sodium boils IIRC at about red heat but, in a vacuum (and that's the circumstances where you would usually get sodium vapour) it will generate significant vapour at a lower temperature.

A bit of web searching suggests the sodium lamps run at about 250C.

That's far too cold to excite the atoms to emit visible light, so it's far too cold to promote sodium atoms to the excited state that emits the yellow "sodium light".

Certainly the lamps run cool enough that , if it were not for the electric discharge inside them, they wouldn't glow visible at all.