Here's a breakdown:
* Hydrogen (H2): Makes up about 89% of Jupiter's atmosphere.
* Helium (He): Makes up about 10% of Jupiter's atmosphere.
* Trace amounts of other gases: These include methane, ammonia, water vapor, and others.
While Jupiter has a small solid core, it's extremely deep within the planet and its composition is not fully understood. The vast majority of Jupiter's mass is in its gaseous atmosphere.