The total number of orbitals present for principal quantum number,$n=4$ is

The electrons,identified by quantum numbers $n$ and $l$ as $(i) n = 4, l = 1$,$(ii) n = 4, l = 0$,$(iii) n = 3, l = 2$,$(iv) n = 3, l = 1$,can be placed in order of increasing energy,from the lowest to highest,as:

Which electronic configuration for oxygen is correct according to Hund's rule of maximum multiplicity?

The shape of $2p$ orbital is

Two statements are given below:
Statement $I$: In $H$ atom,the energy of $2s$ and $2p$ orbitals is same.
Statement $II$: In $He$ atom,the energy of $2s$ and $2p$ orbitals is same.
The correct answer is:

The magnetic quantum number for a $d$-orbital is ...... .