Final answer:
Jovian planets like Uranus and Neptune have compositions dominated by icy and rocky building blocks rather than hydrogen and helium gas. Their different compositions and formation processes explain why common usage of gas, ice, and rock does not apply to these planets.
Step-by-step explanation:
The common usage of gas, ice, and rock falls apart on Jovian planets like Uranus and Neptune because of their different compositions and formation processes. Jupiter and Saturn captured a significant amount of gas from the nebula, resulting in a composition dominated by hydrogen and helium. On the other hand, Uranus and Neptune captured less gas and have compositions dominated by icy and rocky building blocks that made up their large cores. The remaining lighter gases were blown away by the solar wind from the young Sun. This explains why common usage of gas, ice, and rock does not apply to Jovian planets.