Are orbitals of equal energy are occupied by one electron before any single electron is occupied by a second electron . which rule applies?

Sun is explosive itself spread 9 planets.earth is 3rd explosive in the solar system about 500 hundred million years ago . first earth became ice age and freezing climate.centre of earth magma. north zone is artic . south is anatric

They can measure  the amount of energy gained or lost

Answer246 k;