Which of the following explains the sequence of filling the electrons in different shells?

Number of electrons in the outermost orbit of the element of atomic number $15$ is

There is no difference between a $2p$ and a $3p$ orbital regarding

The quantum number which explains the line spectra observed as doublets in the case of hydrogen and alkali metals, and doublets and triplets in the case of alkaline earth metals is:

When the $3d$ orbital is complete,the next electron will enter the

The electronic configuration of the phosphide ion $(P^{3-})$ is similar to which of the following?