The maximum number of electrons that can be accommodated in a shell with $n=4$ is:

The shape of $d_{xy}$ orbital will be

$A$ neutral atom has $2, 8,$ and $7$ electrons in its $K, L,$ and $M$ shells,respectively. What is the total number of electrons in the $p$-orbitals?

Which of the following orbitals has two angular nodes?

The number of unpaired electrons in the ground state of a nickel atom is $(Atomic \ number \ of \ Ni = 28)$.

Statement $1$: The energy of an electron is determined by the principal quantum number.
Statement $2$: The principal quantum number $(n)$ indicates the distance of the electron from the nucleus.