If two electrons in the same atom have the same four quantum numbers, then they must have the same energy. a. trueb. falsec. They cannot both have the same four quantum numbers.

To solve this question, we will rely on the Pauli exclusion principle, which warns that from quantum mechanics two or more identical fermions (particles with spin of the whole medium) cannot occupy the same quantum state within a quantum system simultaneously. Therefore, when two electrons have the same n, l and ml, then they are in the same orbital. But they can't have the same energy. Hence, the energy is different.

Therefore the correct answer is B. False.