( ( ( One proton ) ( with ( ( one electron ) ( ( circulating around ) it ) ) ) ) ( ( is ( a ( hydrogen atom ) ) ) . ) )
(ROOT (S (NP (NP (CD One) (NN proton)) (PP (IN with) (NP (NP (CD one) (NN electron)) (VP (VBG circulating) (PRT (RP around)) (NP (PRP it)))))) (VP (VBZ is) (NP (DT a) (NN hydrogen) (NN atom))) (. .)))
One proton with one electron circulating around it is a hydrogen atom.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD one) (NNS electrons)) (PP (IN in) (NP (DT the) (NN hydrogen) (NN atom))))) (. .)))