The principal quantum number $(n)$ represents:

The total number of magnetic quantum numbers for a $d$-orbital is given by

Which of the following sequences is correct according to the Aufbau principle?

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:

For an electron with $n = 3$,there is only one radial node. The orbital angular momentum of the electron will be

The two electrons $X$ and $Y$ have the following sets of quantum numbers:

$X: n=3, l=2, m=-2, s=+1/2$

$Y: n=3, l=0, m=0, s=+1/2$

Which of the following is the correct statement?