Question

What is the structural difference between a 2P and a 3P orbital?

Answer 1

A `3p` orbital has a spherical node.

Explanation:

All `p` orbitals have a characteristic dumbbell shape with a nodal plane perpendicular to the orbital axis.

We see this in the `2p` orbitals.

(from chemwiki.ucdavis.edu)

The `3p` orbitals have the same general shape and are larger than `2p` orbitals, but they differ in the number of nodes.

You have probably noticed that the total number of nodes in an orbital is equal to `n-1`, where `n` is the principal quantum number.

Thus, a `2p` orbital has 1 node, and a `3p` orbital has 2 nodes.

Nodes can be either angular or radial.

The number of angular nodes is equal to `l`, where `l` is the azimuthal quantum number.

Since all p orbitals have `l = 1`, they all have one angular node, and that is the nodal plane.

Radial nodes are spherical. The number of radial nodes is `n-1-l`.

Hence, a `2p` orbital has no radial nodes, while a `3p` orbital has one.

(from www.villierspark.org.uk)

Here's a computer-generated image of the three `3p` orbitals without the spherical node drawn in.

(from fineartamerica.com)

Can you see the spherical node?