Question

Can we move only one electron from its orbit to another orbit of lower energy without moving other electrons of the atom? well i think it cannot happen but if it can happen pls tell how

Answer 1

Yes, it can happen.

If all the lower energy orbits are already filled with electrons, then it cannot happen since the lower orbitals will already be full, hence another electron will have to move.

However, if the lower energy orbits are not full (for instance if one excited electron goes back to its normal state), then it can happen.