Answer:
an electrically charged atom or group of atoms formed by the loss or gain of one or more electrons, as a cation (positive ion), which is created by electron loss and is attracted to the cathode in electrolysis, or as an anion (negative ion), which is created by an electron gain and is attracted to the anode.
Gases do not conduct heat well.
Answer:
Just like lightning, the spark you see is the discharge of static electricity that equalizes the charges. When you touch a metal object and get a shock, electrons are travelling in between you and the object to equalize the charges of the two objects. The light that is seen is the plasma created by electrons jumping between objects which heats the air surrounding them.