* Hydrogen (H2): Approximately 89.8%

* Helium (He): Approximately 10.2%

These two elements make up the vast majority of Jupiter's atmosphere. However, trace amounts of other elements and compounds are also present, including:

* Methane (CH4): Creates the distinct reddish-brown color of Jupiter's clouds.

* Ammonia (NH3): Forms icy clouds in Jupiter's upper atmosphere.

* Water (H2O): Located deeper in the atmosphere, forming clouds that are not visible from Earth.

* Phosphine (PH3): A rare gas found in the upper layers of Jupiter's atmosphere.

* Hydrogen sulfide (H2S): Contributes to the red and brown colors of Jupiter's clouds.

It's important to note that:

* These trace elements are still significant in terms of their impact on Jupiter's atmosphere, climate, and appearance.

* The composition of Jupiter's atmosphere varies with altitude, with heavier elements becoming more concentrated at lower depths.

* The exact composition of Jupiter's atmosphere is still being studied and refined.

Overall, Jupiter's atmosphere is a complex and dynamic environment, with its composition playing a key role in shaping the planet's unique characteristics.