How does the orbital energy change as the nuclear charge increases from $Ne$ to $Ca$?

Arrange the following orbitals in decreasing order of energy:
$A$. $n = 3, l = 0, m = 0$
$B$. $n = 4, l = 0, m = 0$
$C$. $n = 3, l = 1, m = 0$
$D$. $n = 3, l = 2, m = 1$
The correct option for the order is:

Which of these species will have a non-zero magnetic moment?

In the case of a hydrogen atom,which of the following transitions does not involve the absorption or emission of energy?

How many unpaired electrons are present in the $Ni^{2+}$ cation (atomic number $= 28$)?

The correct set of four quantum numbers for the outermost electron of potassium $(Z=19)$ is