The $2p$ and $3p$ orbitals exhibit distinct differences in both their energy levels and the spatial regions where electrons are likely to be found.

In atomic theory, the principal quantum number, denoted as $n$, determines both the energy level and the size of an electron’s orbital. The $2p$ and $3p$ orbitals are characterized by their principal quantum numbers: $2$ for the $2p$ orbital and $3$ for the $3p$ orbital. Consequently, the $3p$ orbital is positioned at a higher energy level and has a larger spatial extent compared to the $2p$ orbital. This implies that an electron residing in a $3p$ orbital is situated further from the nucleus and possesses greater energy than an electron in a $2p$ orbital.

The letter ‘p’ in $2p$ and $3p$ signifies the orbital’s shape, which is generally dumbbell-shaped for all ‘p’ orbitals. However, as the principal quantum number increases, the size of the ‘p’ orbital also increases. Therefore, the $3p$ orbital is larger than the $2p$ orbital, indicating that an electron in a $3p$ orbital has a higher probability of being located farther from the nucleus than an electron in a $2p$ orbital.

The energy difference between the $2p$ and $3p$ orbitals arises from the increased distance of the $3p$ electrons from the nucleus. Electrons in a $3p$ orbital experience shielding from the positive charge of the nucleus due to the presence of the $2p$ electrons. This shielding effect diminishes the attractive force between the nucleus and the $3p$ electrons, allowing them to occupy a higher energy level.

In summary, the primary distinctions between the $2p$ and $3p$ orbitals lie in their energy levels and sizes. The $3p$ orbital is characterized by a higher energy level and a larger volume compared to the $2p$ orbital, owing to the increased distance of the $3p$ electrons from the nucleus and the shielding effect provided by the $2p$ electrons.