How does the Bohr model help identify valence electrons for an element?

Bohr models are used to predict reactivity in elements. Reactivity refers to how likely an element is to form a compound with another element. When looking at Bohr models, we look at its valence electrons (the electrons on the last energy level) to determine reactivity.

Explanation:

it cools slower in the earth meaning the crystals have more time to form than lava on the surface