No, when an electron absorbs a photon and transitions to a higher energy level or orbital, it does not necessarily change its spin. The spin of an electron is an intrinsic property that remains constant unless influenced by an external magnetic field or other interactions.
When an electron absorbs a photon, it gains energy, and it can move to a higher energy level or orbital. The energy change is related to the difference in energy levels between the initial and final states. The electron can move to an unoccupied orbital if it is energetically allowed, but its spin does not need to change during this process.
The Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers, which includes spin. Each orbital can accommodate a maximum of two electrons with opposite spins (one "up" and one "down"). So, if the electron transitions to an unoccupied orbital, it will typically have the opposite spin compared to the electron that was already present in that orbital. This allows the electron to occupy the orbital without violating the exclusion principle.
In summary, while the absorption of a photon can result in the excitation of an electron to a higher energy level or orbital, it does not necessarily cause a change in the electron's spin unless it interacts with an external magnetic field or other influences.