S < 2s < 2 p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f~5d < 6p < 7s <5f~6d...
, 4f-, - 5d-. 5f- 6d-.
, , , . , .
, . - . 1927 . .
, : , , .
( ) , , .
, , 2-. , 2-. :
. ( ) ( ) .
s- ( ) , p- ( ) - , d- ( ) - . .
30 :
, , .
() :
1s22s22p63s23p6... ..
, 3d5 - 5 3d-.
, , , :
1s2 = [He]
1s22s22p6 = [Ne]
1s22s22p63s23p6 = [Ar]
, 1s22s22p63s23p5, [Ne]3s23p5. , .