Why are some of the planets in your solar system called the inner planets?
Because they are in the asteroid belt. The planets that are outside of the asteroid belt are called the outer planets.
The first eight planets in the solar system, counting from the sun are the following: Mercury, Venus, Earth, Mars. These are called the "Inner planets". Jupiter, Saturn, Uranus, Neptunus. These are called the "Outer planets". The asteroid belt between Mars and Jupiter forms the boundary between the inner solar system and the outer solar system. These 8 planets are the only planets known in our solar system.
The "inner planets" are called inner planets because they are relatively near to the Sun, in the inner part of the Solar System. They are also called the "rocky planets" because they are mainly made of rocks. The "outer planets" are also called "gas giants" and are composed mostly of gases or liquefied gas.
Terrestrial planets are denser, smaller, and rockier planets than those of gas planets. They reside in the inner solar system because during the formation of the solar system, the spinning disk that formed the solar system caused all of the denser objects to collect together in the center. These denser objects are composed of rock and metal, and these are terrestrial planets.
The zone from the main asteroid belt (between Mars and Jupiter) inward to the Sun is informally called the inner solar system and the zone from beyond the asteroid belt to just past Neptune is called the outer solar system. The inner solar system contains the planets that are solid, rock-like -- Mercury, Venus, Earth and Mars. The outer solar system contains the gas planets Jupiter, Saturn Uranus and Neptune. The difference is the mainly…