Sometimes, there is an absolute limit on the number of terms an officeholder can serve, while, in other cases, the restrictions are merely on the number of consecutive terms.
For example, Maxwell's Equations would always be capitalized, while quantum mechanics is usually un-capitalized. I searched half a dozen sites for an answer to this but found no clue about a rule. So go either way that makes you happy, but (most of all) be consistent.
Because the states an electron occur only at discrete energy levels, they are said to be quantized. The word quantum comes from a Latin word meaning âhow muchâ. The branch of physics that provides the current model of the Hydrogen atom is called quantum mechanics.