Which orbital is represented by the wave function $\Psi_{310}$?

The angular part of the wave function for an orbital is given by $\psi_{(\theta, \phi)} = \left( \frac{15}{4\pi} \right)^{1/2} \sin \theta \cos \theta \sin \phi$,where $\theta$ is the angle from the $z$-axis. The angular node$(s)$ are:

Number of completely filled orbitals in xenon atom $(Xe)$ is

The electronic configuration of calcium ion $(Ca^{2+})$ is

Which of the following ions has $18$ electrons in its outermost shell?

The principal quantum number $(n)$ represents: