Argon is more dense than air.
Xenon.
Helium.
Neon
It is a noble gas and so very unreactive.
The most common name for it is a "Noble gas" EDIT: Also Called An "Inert Gas"
LPG sinks to the floor as it is heavier than air.LPG sinks to the floor as it is heavier than air.
Argon.
Helium.
Cold air sinks.
Helium
Neon
Nitrogen.
No. Neon is a noble gas and is unreactive.
Helium. Hydrogen works too but it tends to blow up. Helium is an inert gas that is very unreactive so it makes the best option.
Krypton is an unreactive gas.
It is a noble gas and so very unreactive.
No. Neon is a noble gas and is unreactive.
I have no idea :L