All of the outer planets are made of hydrogen, helium and ice. Mercury is known for its large iron core, Mercury is the closest planet to the sun. Mercury is drying hot and airless. Venus is the second planet away from the sun. Venus has a carbon dioxide atmosphere.
Earth is the only planet with life and liquid on it.
Earth is the third planet away from the sun. The fourth planet away from the sun is Mars. Mars has an atmosphere of carbon dioxide. Mars looks like red and orange dust. It is cold and dry.