Atomic Mass is the count of how many protons and neutrons an element contains. So, there is not really an answer to your question. It would depend upon what elements the gas is made up of.
The gas with atomic mass of 16 and has 8 neutrons is oxygen.
Helium with an atomic mass of 4.00260
There is no such noble gas with an atomic mass of 30. The mass of neon is 20 and the mass of the next noble gas, argon, is 40
Chlorine gas is Cl2. Cl's atomic mass is 35.45 and that x 2 is 70.9
Atomic mass increases from top to bottom and left to right on the periodic table. In each row, the noble gasses have the highest atomic mass. As you travel down that column, also called a group or family, the noble gasses increase in atomic mass. The naturally occurring noble gas with the highest atomic mass is Radon (Rn; atomic mass = 211.4 amu). In 2002, the unstable element Ununoctium was synthesized, and although it is a member of group 18, it was later determined to be a solid at room temperature, so it is not classified as a noble gas.
The gas with atomic mass of 16 and has 8 neutrons is oxygen.
Helium with an atomic mass of 4.00260
Radon has atomic mass of 222. There is isotope of Radon with mass number 226. Radon is a Nobel gas.
Argon is a non meta element. Atomic mass of it is 40.
No halogen gas has a mass of under 15 atomic mass units. The closest is fluorine, at 19.0 atomic mass units.
Neon
Neon.
Oxygen - Atomic Mass: 15.9994.
Hydrogen is a gas. Mass number of it is 2.
There is no such noble gas with an atomic mass of 30. The mass of neon is 20 and the mass of the next noble gas, argon, is 40
Chlorine gas is Cl2. Cl's atomic mass is 35.45 and that x 2 is 70.9
Neon