Maximum electrons in a $d$-subshell are

The orbital with $4$ radial and $1$ angular nodes is

The order of filling of electrons in orbitals in $Ti$ is

If the electronic configuration of a nitrogen atom were $1s^7$,its energy would be lower than the ground state configuration $1s^2 2s^2 2p^3$ because the electrons would be closer to the nucleus. However,the configuration $1s^7$ is not observed. Which of the following principles is violated?

In the following pairs,which orbital experiences greater nuclear attraction?
$(i)$ $4f$ and $5d$ $(ii)$ $4d$ and $5s$ $(iii)$ $7s$ and $5f$ $(iv)$ $7p$ and $5p$
$(v)$ $3d$ and $3f$

An $e^-$ has a magnetic quantum number $(m_l)$ of $-3$. What is the minimum possible principal quantum number $(n)$ for this electron?