To make life even more complicated, the l quantum number values are often referred to using an old-fashioned spectroscopic notation. In that notation s, p, d, f, g... indicate l = 0,1,2,3,4... The syntax is best explained by example. For instance, an iron atom with 26 electrons would have its electronic configuration labeled as:
Note that the last level could hold 10 electrons although only 8 were needed to reach 26.
Spectroscopic notation is convenient because chemical properties of atoms are primarily determined by either the number of electrons it takes to fill the last shell or the number of excess electrons beyond the last filled shell.
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