Explain in terms of charge carriers why the resistance of copper is less than that of CuSO4 solution, which is less than that of hydrogen gas
This is the question directly asked for homework, and I'm not quite sure if I have got the right end of the stick, nor how to answer it. I understand that 'charge carriers' in metals are delocalised electrons, positive and negative ions in salt solutions and ions & electrons in gases when they are made into plasmas by heating. Is the increase in resistivity down to size of charge carriers, and/or how much they are vibrating due to temperature (i.e. for gases to conduct they must be very hot)?
I know this question is a bit stupid but neither my teacher nor the textbook are very helpful, and I would really appreciate any help. Many thanks!