The maximum number of electrons that can have principal quantum number,$n=3$,and spin quantum number,$m_s=-1/2$,is

What would be the electronic configuration of $Cs (Z=55)$ in each case?
$(a)$ If there were three possibilities of the electron spin.
$(b)$ If the quantum number,$l$,could have the value $n$,and if all the rules governing electron configuration were otherwise valid.

What is the number of radial nodes in the $2s$ orbital?

Which of the following sets of quantum numbers represents the highest energy of an atom?

For the configuration shown in the image,which rule is violated $:-$

Calculate the value of $(n + l)$ for the $3d$ orbital.