some elements are not but are just chemically bonded.
put simply, some is
Neon is a gas at room temperature.
At atmospheric temprature and at room temprature it is solid state element.
Hydrogen is not a liquid at room temperature. H2 changes from gas to liquid state at about -253oC .
yes hydrogen is in gases state at room temprature because it is naturality of hydron
depends on what temprature the room is.
Solid
only solid state mater can be melt not any gas, but is any gas is compressed to form solid then it can have a melting point and that will be lower then room temprature at atmospheric pressure
HF is a very corrosive gas at room temperature. It can even etch glass!
At room temprature only mercury. Gallium melts at body temprature.
Air is always a gas.
It depends on the type of heater you have. It may be maintaining the room temprature or it may be warming up ( just like how air conditioners start hot )
it is liquid at room temprature