How is an electron in an atom identified? State the parameters used.

Match the quantum numbers with the information provided:

Quantum Number	Information
$(1)$ Principal quantum number	$(A)$ Spatial orientation of the orbital
$(2)$ Azimuthal quantum number	$(B)$ Energy and size of the orbital
$(3)$ Magnetic quantum number	$(C)$ Electron spin
$(4)$ Spin quantum number	$(D)$ Shape of the orbital

Statement $A$: In a potassium atom,the $19^{th}$ electron enters the $4s$-orbital instead of the $3d$-orbital.
Reason $R$: The $(n + l)$ rule is followed to determine the minimum energy of an orbital.

What is the difference between the $2s$ orbital of hydrogen and the $2s$ orbital of other multi-electron atoms?

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.

Which of the following pairs of atoms or ions have the same electronic configuration?