Why are orbitals named as s, p, d and f? Is there any reason for that?
In: Chemistry
Yes, actually; but the reasons are merely historical now.
As you might know, there are several *quantum numbers* that identify where an electron “is,” or what shell it fits into. One of those numbers is the *angular momentum number* ℓ, and it’s this number we’re interested in.
In the early days of spectroscopy, scientists noted that some series of spectral lines of alkali metals — those corresponding to ℓ-values of zero through three — appeared to be **s**harp, **p**rincipal in nature, **d**iffuse in nature, and **f**undamentally related to hydrogen lines, in order.
The other commenter is right, but the reason it’s called a, p, d, and f are short for sharp, principal, diffuse, and fundamental. You can remember the first two by their shapes, s groups electrons follow a spherical orbit, while p group electrons are polar(they go to one side, then the opposite). D orbitals are mostly planar(they occupy a flat area) which is why they are diffuse, and f orbitals are fundamental in that they are found pretty equally in all 8 directions.
A simple google search for “Orbital Names” will give you the answer:
From [https://www.thoughtco.com/angular-momentum-quantum-numbers-606461](https://www.thoughtco.com/angular-momentum-quantum-numbers-606461)
>The orbital names s, p, d, and f stand for names given to groups of lines originally noted in the spectra of the alkali metals. These line groups are called sharp, principal, diffuse, and fundamental.
It was a revelation when I realized that the strange shape of the spd and f orbitals matches the shapes of spherical harmonic functions. It’s the same as a Taylor series describing a wave but the orbitals are 3d.
That’s when I realized that the shape isn’t what the electron looks like, it’s the probability of the electron at each point in space around the protons in the center.
I don’t know, but I remember that Silly Putty Doesn’t Fly from high school chemistry 40 years ago.
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