No, Uranus is not 100% gas it's an "ice giant" with a small rocky core, a massive icy mantle (water, methane, ammonia), and a gaseous atmosphere.
Uranus Structure:
1. Core (center):
- Small rocky/metallic core
- About 0.5 Earth masses
- High pressure and temperature
2. Mantle (largest layer):
- "Ices": Water, methane, ammonia
- Not frozen solid—compressed liquids
- ~13.5 Earth masses
- Most of the planet's mass
3. Atmosphere (outer layer):
- Hydrogen and helium gas
- Methane (gives blue-green color)
- Relatively thin compared to mantle
Classification:
- Ice giant: Not a gas giant like Jupiter/Saturn
- Different composition and structure
- More "ice" (compressed liquids) than gas
Importants Points:
- Not 100% gas: Has rocky core and icy mantle
- Classification: Ice giant (not gas giant)
- Structure: Core, icy mantle, gaseous atmosphere