Answer :
The outer planets are further away, larger and made up mostly of gas. The inner planets (in order of distance from the sun, closest to furthest) are Mercury, Venus, Earth and Mars. After an asteroid belt comes the outer planets, Jupiter, Saturn, Uranus and Neptune.
The main difference between inner and outer planets is that outer planets are larger and are mainly made of gas. The inner planets are Venus, Mercury, Mars and Earth, while the outer planets are considered to be Saturn, Uranus, Neptune and Jupiter.