The electronic configuration of the phosphide ion is similar to which of the following?

The total number of orbitals present for principal quantum number,$n=4$ is

The number of unpaired electrons in a carbon atom in the excited state is:

The energy of atomic orbitals in a given shell follows the order:

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.

The number of waves made by an electron moving in an orbit having a maximum magnetic quantum number $(m_l) = 3$ is: