Why are minerals found in "large" quantities and not scattered throughout the earth as individual atoms?

Question

Heavier elements are created in stars. After stars die they scatter these heavier elements throughout the universe. These elements eventually gather to form planets. But why do we find "chunks" of gold, silver, etc. and not scattered atoms throughout the earth. In other words, how do the atoms of these elements come together to form chunks of the same element involving billions and billions of atoms?

Answer 1

The biggest reason is fractional distillation and freezing.

The idea is that if you have a big blog of homogeneous substance and it gradually cools, eventually one element or compound will reach its freezing point and come out of solution first. So if things cool slowly enough there will be a high concentration of whatever substance it was that came out of solution first.

This gradually happens to one compound after another until you have the compounds more or less separated. Similar concept to how oil is refined.

There are other processes too, but the idea is the same. If things change slowly enough one thing will be removed after another and you will have distinct compounds.