에너지 수준 (N) 궤도 전자 **
-1 1S 2
-2 1s, 2s, 2p 8
-3 1s, 2s, 2p, 3s, 3p 18
-4 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p 32
-5 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 5s, 4d, 5p 50
-6 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 5s, 5p, 5d, 6s, 4f, 5d, 6p 72
-7 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 5f, 6s, 6p, 6d, 7p 98
-8 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 5f, 5g, 6s, 6p, 6d, 6f, 7s, 7p 128
