( Hydrogen ( ( ( ( is ( the ( simplest atom ) ) ) , ) ( with ( ( ( ( ( one proton ) , ) ( one electron ) ) and ) ( no ( pesky neutrons ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Hydrogen)) (VP (VBZ is) (NP (DT the) (JJS simplest) (NN atom)) (, ,) (PP (IN with) (NP (NP (CD one) (NN proton)) (, ,) (NP (CD one) (NN electron)) (CC and) (NP (DT no) (JJ pesky) (NNS neutrons))))) (. .)))
Hydrogen is the simplest atom, with one proton, one electron and no pesky neutrons.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD one) (NNS electrons)) (PP (IN in) (NP (DT the) (NN hydrogen) (NN atom))))) (. .)))