Sunday, August 20, 2017

Inert Gases in Plasma Balls


Recently I have been reading about the fourth state of matter, viz.Plasma. Everywhere I read that plasma is formed when Gases are given enough energy and they lose their electrons to form a "cloud" of free electrons and cations i.e. when gases are ionised.


In a plasma ball, the gas inside the ball is a noble gas. Even though noble gases are chemically inert and won't lose electrons much easily, as compared to other gases I am unable to understand why are they used ?


(Please correct me if I am wrong somewhere.Thank You.)



Answer



Noble gases do not form molecular bonds as easily as other elements, true, because it's usually energetically unfavorable - a molecule containing a noble gas often would have more energy than the reactants.


However, it's not difficult at all to ionize noble gases with a static electric field, or EM radiation, or heating, or other means. That is to say, it is harder to ionize noble gases than other elements with similar electron cloud sizes but incomplete shells, but the difference is so small that it makes no difference in most applications.


In fact, noble gases are desirable for applications like plasma globes because they are non-reactive. If you have a gas inside something that's not supposed to open up, you don't want the gas corroding electrodes, or degrading surfaces, or any other effects caused by more reactive chemicals.


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