( ( The principle ) ( ( states ( that ( ( ( the lowest ) ( - ( ( ( energy orbitals ) ( are ( filled first ) ) ) , ) ) ) ( ( followed successively ) ( by ( higher-energy orbitals ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN principle)) (VP (VBZ states) (SBAR (IN that) (S (NP (NP (DT the) (JJS lowest)) (PRN (, -) (S (NP (NN energy) (NNS orbitals)) (VP (VBP are) (VP (VBN filled) (ADVP (RB first))))) (, ,))) (VP (VBD followed) (ADVP (RB successively)) (PP (IN by) (NP (JJ higher-energy) (NNS orbitals))))))) (. .)))
The principle states that the lowest- energy orbitals are filled first, followed successively by higher-energy orbitals.
(ROOT (S (NP (NP (NNS Electrons)) (PP (IN in) (NP (NP (JJ successive) (NNS atoms)) (PP (IN on) (NP (DT the) (JJ periodic) (NN table)))))) (VP (VBP tend) (S (VP (TO to) (VP (VB fill) (NP (JJ low-energy) (NNS orbitals)) (ADVP (RB first)))))) (. .)))