( There ( ( are ( ( four ( valence electrons ) ) ( on ( a ( neutral ( carbon atom ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD four) (JJ valence) (NNS electrons)) (PP (IN on) (NP (DT a) (JJ neutral) (NN carbon) (NN atom))))) (. .)))
There are four valence electrons on a neutral carbon atom.
(ROOT (S (NP (NNP Carbon)) (VP (VBZ has) (NP (CD four) (JJ valence) (NNS electrons))) (. .)))