Honors Chemistry Practice Exam

The main idea here is quantization: electrons in atoms are described by specific, discrete values that come from solving the quantum mechanical description of the atom. These discrete values are called quantum numbers. They label the allowed states an electron can occupy: the principal quantum number sets the energy level and size of the orbital, the azimuthal quantum number describes the subshell’s shape, the magnetic quantum number tells how the orbital is oriented in space, and the spin quantum number indicates the electron’s intrinsic spin. An orbital, by contrast, is a region of space where there’s a high probability of finding the electron, not the discrete numbers themselves. The ground state is simply the lowest-energy state, and quantum theory is the broader framework that describes all of this. So the term that refers to those discrete values is quantum numbers.