Which of the following orbitals is represented by $n=3$ and $l=2$?

The electronic configuration $1s^2 2s^2 2p_x^1 2p_y^1 2p_z^1$ corresponds to which of the following elements?

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.

Write down about the Hund's rule.

The spin angular momentum for an electron is given by .......

The atomic number of an element is $17$. The number of orbitals containing electron pairs in its valence shell is