Which electronic configuration represents a noble gas?

The electronic configuration of an element with atomic number $7$ i.e. nitrogen atom is

The general configuration of the outermost and penultimate shell is $(n - 1)s^2 (n - 1)p^6 (n - 1)d^x ns^2$. If $n = 4$ and $x = 5$,then the number of protons in the nucleus will be:

The electronic configuration of the valence shell of $Cu$ is $3d^{10}4s^{1}$ and not $3d^{9}4s^{2}$. How is this configuration explained?

The orbital angular momentum of a $p-$ electron is given as

The number of radial (spherical) nodes in a $4p$ orbital is $....$.