( ( ( The ( outer ( electron orbital ) ) ) ( of silicon ) ) ( , ( ( like ( that ( of carbon ) ) ) ( , ( ( has ( four ( valence electrons ) ) ) . ) ) ) ) )
(ROOT (S (NP (NP (DT The) (JJ outer) (NN electron) (NN orbital)) (PP (IN of) (NP (NN silicon)))) (, ,) (PP (IN like) (NP (NP (DT that)) (PP (IN of) (NP (NN carbon))))) (, ,) (VP (VBZ has) (NP (CD four) (JJ valence) (NNS electrons))) (. .)))
The outer electron orbital of silicon, like that of carbon, has four valence electrons.
(ROOT (S (NP (CD Four) (JJ valence) (NNS electrons)) (VP (MD can) (VP (VB be) (VP (VBN found) (PP (IN in) (NP (DT a) (NN carbon) (NN atom)))))) (. .)))