what are angular nodes?

Dear student,

An angular node is usually a planar or conical surface in which there is no electron density.  The p orbitals have a planar node through the center, d orbitals have two conical nodes for the d_z² (imagine drawing cones around nodes of the same sign and those are the conical angular nodes) and 2 planar nodes for the rest , and so on.  The number of angular nodes matches the l quantum number for the subshell.  

Here is a nice website that has pictures of many of the different atomic orbitals.  http://winter.group.shef.ac.uk/orbitron/ 

Hope this helps you some. 

All the best