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

1 Answer
Jan 23, 2016

Answer:

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.

2p nodal surface
(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.

3p spherical node
(from www.villierspark.org.uk)

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

3p
(from fineartamerica.com)

Can you see the spherical node?