Which of the following outer electronic configurations represents argon?

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 $3f$

The energy of orbitals in a hydrogen atom can be determined by which of the following quantum numbers?

The total number of electrons that can be accommodated in all the orbitals having principal quantum number $n = 2$ and azimuthal quantum number $l = 1$ is

An electronic transition from $1s$ orbital of an atom causes

Which electron,$2s$ or $2p$,is more strongly attracted to the nucleus? Explain.