The maximum number of possible electrons in a subshell with $n=3$ and $l=2$ is

If $Br^{-}$ configuration is $[Ar]\, 3d^{10}\,4s^2\,4p^6$,then $Br^{+2}$ configuration will be identical to which element?

Explain,giving reasons,which of the following sets of quantum numbers are not possible.
$(a)$ $n=0, l=0, m_{l}=0, m_{s}=+\frac{1}{2}$
$(b)$ $n=1, l=0, m_{l}=0, m_{s}=-\frac{1}{2}$
$(c)$ $n=1, l=1, m_{l}=0, m_{s}=+\frac{1}{2}$
$(d)$ $n=2, l=1, m_{l}=0, m_{s}=-\frac{1}{2}$
$(e)$ $n=3, l=3, m_{l}=-3, m_{s}=+\frac{1}{2}$
$(f)$ $n=3, l=1, m_{l}=0, m_{s}=+\frac{1}{2}$

For a $d$-electron,the orbital angular momentum is:

Which of the following sets of quantum numbers is not possible?

When the $3d$ orbital is completely filled,the next entering electron will be in the ....... orbital.