Maximum number of electrons that can be accommodated in the subshell with azimuthal quantum number $l=4$ is

Which of the following are correct?
$(1)$ Electron density in $XY$ plane for $d_{x^2-y^2}$ orbital is zero.
$(2)$ The energy of $3p$-orbital is higher than the energy of $2p$-orbital.
$(3)$ $3p_z$-orbital has one angular node.
$(4)$ $4f$-orbital has no radial node.

The shape of $2p$ orbital is

Write the electronic configuration of chromium $(Cr)$ and copper $(Cu)$. Give reasons for the observed configurations of $Cr$ $(Z = 24)$ and $Cu$ $(Z = 29)$.

How many electrons are present in an atom with atomic number $Z = 104$ for which $(n + l) = 8$?

The electronic configuration of cobalt ($Co$,atomic number $27$) is: