Solids and liquids are better conductors. You can't say which of the two because some solids are more dense than some liquids and vice versa.
Gases are poor conductors of heat and electricity because their particles are widely spaced and have weak intermolecular forces. This means that heat and electrons cannot be transferred efficiently between gas particles, resulting in low conductivity. Liquids and solids, with their closer particles and stronger intermolecular forces, are better conductors than gases.
Air and other gases are usually good insulators but sometimes they can be good conductors
A liquid or a gas will conduct electricity when they have free ions in them. examples would be lead-acid batteries, and fluorescent lamps. Mercury vapour rectifiers are used to conduct quite large currents by virtue of the ionized mercury vapour.
A plasma is an ionized gas ... thus its properties are those of a gas PLUS the fact that it can conduct electricity.
I believe you are referring to plasma, which is an ionized gas. It is the 4th state of matter apart from solids, liquids and gases.
Most metals conduct electricity. Copper and gold are probably the two best conductors. Steel conducts electricity, but it's an alloy not an element. Some other nonmetals also conduct electricity. Experiments are ongoing with carbon for use in computers. Neon is a gas which allows electricity to flow through it, making neon lights. Today Copper is used more than anything else when electricity must move from one place to another predictably.
In terms of the elements, no, with the possible exception of carbon (C) in the form of graphite. The non metal elements are generally the opposite, insulating as opposed to conducting. However, Water with a high salt concentration, and plasma (electrically charged gas) are good conductors.
Liquids have a definite volume but gas do not
Bromine is a liquid at room temperature, and it is located in group 7 of the periodic table, i.e., it is a halogen. It is a non-metal and thus is a poor conductor of both electricity and heat.
There are several well known gas and electricity companies. These companies include Pacific Gas and Electric Company, All Connect Natural Gas and Electricity, and Spark Energy.
Some fire extinguishers have liquid; some have solids; some have compressed gas; some have combinations of gas, liquids and solids.