( ( ( A ( Hydrogen Atom ) ) ( Each ( hydrogen atom ) ) ) ( ( consists ( of ( ( one proton ) ( surrounded ( by ( one electron ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NNP Hydrogen) (NNP Atom)) (NP (DT Each) (NN hydrogen) (NN atom))) (VP (VBZ consists) (PP (IN of) (NP (NP (CD one) (NN proton)) (VP (VBN surrounded) (PP (IN by) (NP (CD one) (NN electron))))))) (. .)))
A Hydrogen Atom Each hydrogen atom consists of one proton surrounded by one electron.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD one) (NNS electrons)) (PP (IN in) (NP (DT the) (NN hydrogen) (NN atom))))) (. .)))