For electrons having principal quantum number $n = 3$,the number of $(i)$ subshells and $(ii)$ orbitals would be respectively:

Which of the following sets of species has the $3^{rd}$ principal energy level $(n=3)$ completely filled?

If the electronic configuration of a nitrogen atom were $1s^7$,its energy would be lower than that of the ground state configuration $1s^2\,2s^2\,2p^3$ due to being closer to the nucleus. However,the $1s^7$ configuration is not observed because it violates which of the following rules?

The five valence electrons of $_{15}P$ are represented as shown in the figure. If the spin quantum number of $B$ and $Z$ is $+1/2$,which of the following groups has three identical quantum numbers?

For the last electron entering the electronic configuration of potassium $(K)$,the values of $n, l,$ and $m$ are respectively .......

The orbital angular momentum of an electron in $2s$ orbitals is