Why Are The Inner Planets Rocky While The Outer Planets Are Gaseous?
The inner planets are made from the gas from the solar nebula that created the sun. The gas is just condensed into microscopic particles, which eventually clumped together to form the rocky bodies they are today. As for the outer planets this theory is not proven but is the leading model: They started out just like the inner planets except with more ice, however they got larger. And with there large masses their gravity became strong enough to hold gases such as hydrogen and helium. As they collected more gas their gravities increases even more allowing them to collect even more gas. Eventually their bodies were made up of more gas than icy rock.
