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:

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

not sure if this what   you'r looking for would be percent composition