Final answer:
The principal quantum number (n) represents the total energy of an electron in the quantum mechanical model of the atom.
Step-by-step explanation:
The principal quantum number (n) in the quantum mechanical model of the atom represents the total energy of an electron in a hydrogen atom. It defines the location of the energy level, also known as the shell number. The energy of an electron in an atom is quantized, and the value of n determines the general range of energy and the probable distances the electron can be from the nucleus.
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