Question: orbital has the least amount of energy?
Answer: At the lowest energy level, the one closest to the atomic center, there is a single 1s orbital that can hold 2 electrons. At the next energy level, there are four orbitals; a 2s, 2p1, 2p2, and a 2p3. Each of these orbitals can hold 2 electrons, so a total of 8 electrons can be found at this level of energy.