Nodes are the spaces where the probability of finding an electron is zero.

Radial nodes are the nodes that appear along the radius of an atom while angular nodes are the nodes that appear along the plane of an angle.

$\mathrm{n}-\mathrm{l}-1=2$

$\mathrm{l}=2$

$\mathrm{n}-2-1=2$

$\mathrm{n}=5$