The orbital angular momentum of an electron in $3s$ orbital is $\frac{xh}{2\pi}$. The value of $x$ is . . . . . . .

The number of valence electrons in one mole of nitride ion is ............ mole.

The shape of $p$-orbital is

Explain the meaning of the $+ve$ and $-ve$ signs in the context of the wave function $\psi$ for an electron.

Which of the following sets of quantum numbers represents the orbital with the highest energy?

For the given quantum numbers $n$ and $l$ of electrons:
$(i) n = 4, l = 1$
$(ii) n = 4, l = 0$
$(iii) n = 3, l = 2$
$(iv) n = 3, l = 1$
Arrange them in the increasing order of their energy.