Ionization

[Seven]

Google's been giving me some pretty vague results on this subject....

 

I have to write a report on one the the elements (for me, lithium), and I decided I'd do a little extra and have a little section on plasma. However, we've never covered it, so I don't really know much about it.

 

Does a gas become a plasma when an electrical current passes through it, or at a certain temperature? Both?

 

Are all the electron shells stripped of electrons, or just some?

 

At what point does lithium become a ionized/recombine? Is that even possible?

 

Thanks a lot. =)

 

 

PS- I'm talking specifically about 7^Li, but 6^Li is stable so I guess that could work for an answer.

 

PPS- Is it true if you bombard 7^Li with protons it turns into 8^Mg and has a nuclear reaction?

[MrSandman]

You in highschool it has been a while. I'm a freshmen taking bio 121.

 

Are all the electrons shells stripped of electrons, no.

 

There is the special section on the periodic table called the noble gases they are He, Ne, Ar, Kr, Xe, and Rn. They are not striped of any of it's valence electrons. All the other ones want to become like noble gases.

 

Li has the highest chance to bond with Cl.

 

Hope this helps a little, I know more, but not quite sure. Expand more on your questions.

[swansont]

If you can pass current through the air, you've achieved breakdown voltage and ionized atoms along the path, so you have a plasma. You can do this thermally; if you have enough atoms in a thermal distribution with high enough energy to ionize when they collide. The number of electrons you strip off will depend on how hot you get the ensemble — it's harder to strip the second and even harder to get the last one.

[MrSandman]

Yeah, proving that they want to be like noble gases.

[Klaynos]

Yeah, proving that they want to be like noble gases.

 

They are not sentient they don't want to be anything.....

[John Cuthber]

Since the noble gases are perfectly able to form plasmas where they have less than the full complement of electrons that's not a reason for mentioning them here. On the other hand, they are as good an example of a plasma as any.

 

"Does a gas become a plasma when an electrical current passes through it, or at a certain temperature? Both?"

Well, both is probably the best answer.

Any atom or molecule on its own in a gas might get ionised. It might be hit by another atom (or whatever) and lose an electron . It might get pulled apart by an electric field or it might get hit by radiation of some sort. In a flame some of the molecules are hot enough to be moving fast enough to chip electrons of molecules and atoms. Some of the maolecules in a candle flame are ionised so it is a plasma. On the other hand, most of the molecules are neutral, only a small frraction are ionised. A candle flame is, therefore, a weak plasma.

 

In a neon lamp the initial ionisation can be caused by the electric field but it's sometimes caused by radiation. The normal background levels of radiation can sometimes do this. Whatever produces the first pair of charged particles- say an electron and a Ne+ ion, they are atracted to the electrodes in the lamp. The elelctron is drawn to the + electrode and the Ne+ ion to the - electrode. Usually, before they get to their destinations they plough into another atom of neon. If they are going fast enough they ionise this atom too. In this way you can readily ionise a lot of gas. After a while many of the atoms are ionised. Some of the ions get hit again and lose a second electron to give Ne++. Of course this is rarer than hitting an unionised atom so there are usually fewer Ne++ ions than Ne+ ions. Higher charged ions are also made, but these are rarer still.

The atoms that get hit might not get ionised. They may just have the electrons knocked away from the nucleus into a higher orbital. When these electrons fall back they give out the excess energy as light.

 

PPS you won't get Mg from Li that way, but you might get Be.

[Seven]

PPS you won't get Mg from Li that way, but you might get Be.

 

Okay, thanks a lot guys!

 

Also, yeah, I meant Be. I have a tendency to mix that and magnesium up for some reason.

 

Anyway, I got my essay in, and my teacher said it looked pretty good. Hopefully an A.