How do 71% know Xenon is a gas, 50% for radon and only 48% for chlorine? It was the original gas used in World War One. Greenish-yellow clouds that people had no defense against so they'd urinate on a cloth and hold it to their airways to neutralize it.
It was a Canadian high school chemistry teacher who allegedly thought to urinate on a cloth whilst in the first gas attack on Ypres. But I don't think most people think of chlorine gas primarily in terms of World War I history.
Mr. Serico would be pround that all these years later, I still remember HONK-ull-briff (HONClBrIF) for the diatomic elements. 10-of-11. Krypton was my kryptonite.
Helium, neon, argon, krypton, xenon, and radon are noble gases. They wouldn't react with the other gases, but radon is radioactive.
Hydrogen is +1, and fluorine and chlorine are -1, so they'd happily bond. Hydrogen fluoride is a poisonous, colorless gas or liquid that becomes hydrofluoric acid in water. Likewise, hydrogen chloride becomes hydrochloric acid.
Oxygen is -2 and will bond with a couple of hydrogens, forming dihydrogen monoxide (water).
Nitrogen is -3 and will grab three hydrogens to become trihydrogen mononitride (ammonia), a colorless, irritating gas.
Other reactions that could occur would be oxygen bonding with itself to form O2 (breathable oxygen) and O3 (ozone), and nitrogen forming N2 (the normal nitrogen in air). In fact, most of the oxygen would already be double-bonded O2 and nitrogen triple-bonded N2, which they're very happy to be. It would take a spark to break them and get them to bond with the hydrogen.
As for what would happen if you were in a room with all of those gases: you would die. You would quickly succumb to the chlorine and fluorine gases, which are extremely reactive and would burn your skin and lungs with each breath, as they form powerful acids in the water in your cells. The helium would cause you to scream like a member of The Chipmunks during your rapid, tragic death, and the radon would make your corpse radioactive, necessitating a lead coffin.
Bromine and iodine also exist as gases at room temperature and standard pressure though their main forms are not gas.
Hydrogen is +1, and fluorine and chlorine are -1, so they'd happily bond. Hydrogen fluoride is a poisonous, colorless gas or liquid that becomes hydrofluoric acid in water. Likewise, hydrogen chloride becomes hydrochloric acid.
Oxygen is -2 and will bond with a couple of hydrogens, forming dihydrogen monoxide (water).
Nitrogen is -3 and will grab three hydrogens to become trihydrogen mononitride (ammonia), a colorless, irritating gas.
Other reactions that could occur would be oxygen bonding with itself to form O2 (breathable oxygen) and O3 (ozone), and nitrogen forming N2 (the normal nitrogen in air). In fact, most of the oxygen would already be double-bonded O2 and nitrogen triple-bonded N2, which they're very happy to be. It would take a spark to break them and get them to bond with the hydrogen.