All terms in this list:

inner planets: mercury, venus, earth and mars

mercury: smallest terrestrial planet and closest to the sun

venus: second from the sun and similar to earth in size and mass

mars: fourth from the sun and often called the red planet

outer planets: Jupiter, Saturn, Uranus and Neptune

gas giants: the first four outer planets - they are so large and massive that they do not have solid surfaces

Jupiter: largest and most massive planet

Saturn: The second largest planet and is famous for its large rings

uranus: seventh planet from the sun

Neptune: eighth planet from the sun. A cold, blue planet. Atmosphere contains visible clouds

Pluto: farthest planet from the sun