Final answer:
The combination of quantized energy levels and the Pauli exclusion principle is an important concept in quantum mechanics. It determines the electron configurations and the arrangement of electrons in different orbitals and subshells.
Step-by-step explanation:
The combination of quantized energy levels and the Pauli exclusion principle is an important concept in quantum mechanics. In an atom, electrons occupy specific energy levels, which are quantized. These energy levels are represented by the quantum numbers n, l, m, and s. The Pauli exclusion principle states that no two electrons in an atom can have all the same quantum numbers, which means that each electron must have a unique set of quantum numbers.
For example, consider the electron configuration of hydrogen. The electron in the 1s orbital has quantum numbers n=1, l=0, m=0, and s=1/2. According to the Pauli exclusion principle, no other electron in the hydrogen atom can have these exact quantum numbers. Therefore, the second electron in hydrogen must occupy a different energy level or orbital.
This combination of quantized energy levels and the Pauli exclusion principle allows for a systematic organization of electrons in an atom. It determines the electron configurations and the arrangement of electrons in different orbitals and subshells.