Question

Which elements are most common on earth? Are these elements found uniformly on other planets?

Answer 1

Iron, Oxygen, Silicon, and Magnesium are the most abundant elements on Earth.

Explanation:

The elements in order of abundance on Earth by mass are:
Iron 32.1%
Oxygen 30.1%
Silicon 15.1%
Magnesium 13.9%
All of the other elements together total the remaining amount.

The element abundances are not uniform across other planets. The inner rocky planets Mercury, Venus, Earth and Mars have similar makeup. The outer planets have completely different combinations of elements. Jupiter is mainly Hydrogen.