Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I know that neon is used in advert signs due to its inertness. However, I am not entirely sure how the inertness is exploited. I think it is because Ne being inert means that after electricity frees an electron we can count on it returning to the ion left behind to emit a photon, whereas for more active elements, the gas may just exist as a plasma?

share|cite|improve this question
Ne is used, 1. because it caused the red glow inside the tube. 2. because even when it exist as plasma, it doesn't react with the filament inside the tube or the glass walls. – Vineet Menon Dec 15 '11 at 17:00
There's a similar reason why incandescent bulbs have a vacuum inside; at high heat and lots of electrons running amuck, most other gases tend to react with metals (oxides, nitrides, etc.), which tend to be less durable than the metals... – user172 Dec 15 '11 at 17:13
@VineetMenon and j-m: I know both of your answers are short, but you should really post them as answers to let the rest of us vote on them. Comments should not have answers but "requests for clarification". – Arnoques Dec 16 '11 at 1:55

Ne is used,

  1. Because it caused the red glow inside the tube, infact you can get a whole array of colors using different noble gases. eg. Ne => Red, Xe => Whitish Blue, Ar => Blue etc. Check Wikipedia for more.
  2. Because even when it exist as plasma, it doesn't react with the filament inside the tube or the glass walls, this helps in the longer life of lamp, and as pointed out by @J.M. this technique finds its use in incandescent lamp where Argon is generally used.
share|cite|improve this answer

protected by Qmechanic Jan 24 '13 at 21:54

Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).

Would you like to answer one of these unanswered questions instead?

Not the answer you're looking for? Browse other questions tagged or ask your own question.