Understanding Electron Orbitals: Exploring Their Size and Positioning

[tahayassen]

I understand that electrons can be in any particular location of an orbital. However, why do they have such a large space for the electron to potentially be in? Shouldn't the electron stick to the proton?

 

[Jano L.]

The size of the orbital is around 0.1 nm. From the human perspective, you can say that electron really does stick to the proton very closely.

 

[kurros]

Well for a proper answer you'll have to look at the solutions to the Schroedinger equation, but you can roughly understand it as being due to the kinetic energy that the electrons have, the fact that they have a wavelength, and because of the uncertainty principle (so you can't locate them precisely if you know they have some certain energy).

Even in the ground state orbital electrons still carry kinetic energy, and so their wavelength is not zero (even though wavelength doesn't exactly make sense since they are not free particles, but forget about that), and so there is a characteristic scale at which they sit around the atomic nucleus which is determined by these things (and their mass). The Bohr model, while not correct, gets this scale about right, so you can look that up (the explanation here relates to being able to "fit" a full wavelength of the electron around the nucleus, in a circle, which is vaguely similar to what is happening)