A paragraph in my text reads
Bonding involves the valence orbitals almost exclusively because these orbitals have the appropriate energies to interact strongly. Examine the electron energy-level diagram of a fluorine atom. The core $1 \mathrm{s}$ orbitals on a fluorine atom are at much lower energies than any of the $n = 2$ orbitals and do not participate effectively in bonding with other atoms. On the other hand, orbitals with $n > 2$ lie at considerably higher energy than the $n = 2$ orbitals. These orbitals can interact, but the resulting orbitals are too unstable to form strong covalent bonds. Therefore, the only orbitals of fluorine that form chemical bonds are the valence orbitals, those with $n = 2$. Typically the highest energy occupied orbitals are the ones used to bond with other atoms.
In contrast this simple paragraph from SparkNotes expresses what I had believed to be the case
The outermost orbital shell of an atom is called its valence shell, and the electrons in the valence shell are valence electrons. Valence electrons are the highest energy electrons in an atom and are therefore the most reactive.
I had thought that the outermost shell, the valence shell, the most energetic shell, and the shell involved in molecular bonds were all the same thing. However, the quoted paragraph of my text says otherwise. Where have I gone wrong?