Uranium, the heaviest of the stable, naturally-occurring chemical elements , is more abundant in the Earth's crust than silver, mercury, or iodine.
= of the stable, naturally-occurring chemical elements
= of the chemical elements to be stable and naturally occurring
= of the elements that are stable and naturally occurring
= stable and naturally occurring of the chemical elements
= chemical elements stable and naturally occurring
= of the stable, naturally-occurring chemical elements
= of the chemical elements to be stable and naturally occurring
= of the elements that are stable and naturally occurring
= stable and naturally occurring of the chemical elements
= chemical elements stable and naturally occurring