oxygen
ammonia and some types of gas based carbon.
oxygen
nitrogen
ozone
Oxygen.
ozone
gas-gas
Oxygen, now about 20% of the atmosphere, was not part of the original atmosphere of hthe Earth. It was produced by plants, after life developed.
The Gas Giants have a deep gas atmosphere and earth have a not so deep atmosphere
Hydrogen gas was not part of Earth's original atmosphere. The early atmosphere primarily consisted of carbon dioxide, water vapor, and nitrogen, among other gases. Hydrogen was likely lost to space due to its low mass and the sun's radiation.
Oxygen gas
Nitrogen
Krypton is found in trace amounts in the atmosphere