Why does the solar system consist of small planets orbiting close to sun and larger on more distant

The inner planets are smaller and rockier

Explanation:

Astronomers divide the planets into two groups in Solar system, the inner planets and outer planets. The inner planets are smaller and rockier and it is closer to the sun. The outer planets are larger, further far away and made of gas

The inner planets are Mercury, Venus, Earth and Mars. The outer planets Jupiter, Saturn, Uranus and Neptune comes after an asteroid belt. In some other planetary systems the gas are close to the sun.

particles in a disk of gas and dust will form Planets. If they orbit the star they are colliding and sticking. The stars wind blows away their gases. So the nearest planets to starts are rockier.