<Dd> n = 1, 2,...</Dd> <P> For example, in caesium (Cs), the outermost valence electron is in the shell with energy level 6, so an electron in caesium can have an n value from 1 to 6 . </P> <Li> The azimuthal quantum number (l) (also known as the angular quantum number or orbital quantum number) describes the subshell, and gives the magnitude of the orbital angular momentum through the relation <Dl> <Dd> L = ħ l (l + 1). </Dd> </Dl> <P> In chemistry and spectroscopy, "l = 0" is called an s orbital, "l = 1" ap orbital, "l = 2" ad orbital, and "l = 3" an f orbital . </P> <P> The value of l ranges from 0 to n − 1, so the first p orbital (l = 1) appears in the second electron shell (n = 2), the first d orbital (l = 2) appears in the third shell (n = 3), and so on: </P> <Dl> <Dd> l = 0, 1, 2,..., n − 1 . </Dd> </Dl> A quantum number beginning in 3, 0,...describes an electron in the s orbital of the third electron shell of an atom . In chemistry, this quantum number is very important, since it specifies the shape of an atomic orbital and strongly influences chemical bonds and bond angles . </Li> <Dl> <Dd> L = ħ l (l + 1). </Dd> </Dl>

The shape of an atomic orbital is determined by which quantum number