chemical element,
element the most favorable environment for a plant or animal; "water is the element of fishes"
gas the state of matter distinguished from the solid and liquid states by: relatively low density and viscosity; relatively great expansion and contraction with changes in pressure and temperature; the ability to diffuse readily; and the spontaneous tendency to become distributed uniformly throughout any container
argon,
atomic number 18,
ar a colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere
atomic number 2,
helium,
he a very light colorless element that is one of the six inert gasses; the most difficult gas to liquefy; occurs in economically extractable amounts in certain natural gases (as those found in Texas and Kansas)
atomic number 36,
krypton,
kr a colorless element that is one of the six inert gasses; occurs in trace amounts in air
atomic number 10,
neon,
ne a colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts
atomic number 86,
radon,
rn a radioactive gaseous element formed by the disintegration of radium; the heaviest of the inert gasses; occurs naturally (especially in areas over granite) and is considered a hazard to health
