( Atoms ( ( consist ( of ( ( a ( central nucleus ) ) ( containing ( ( ( ( protons and ) neutrons ) ( -LRB- ( ( except ( ( hydrogen , ) ( which ( has ( ( ( just ( one proton ) ) and ) ( no neutrons ) ) ) ) ) ) -RRB- ) ) ) ( surrounded ( by electrons ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Atoms)) (VP (VBP consist) (PP (IN of) (NP (NP (DT a) (JJ central) (NN nucleus)) (VP (VBG containing) (NP (NP (NNS protons) (CC and) (NNS neutrons)) (PRN (-LRB- -LRB-) (PP (IN except) (NP (NP (NN hydrogen)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ has) (NP (NP (RB just) (CD one) (NN proton)) (CC and) (NP (DT no) (NNS neutrons)))))))) (-RRB- -RRB-)) (VP (VBN surrounded) (PP (IN by) (NP (NNS electrons))))))))) (. .)))
Atoms consist of a central nucleus containing protons and neutrons (except hydrogen, which has just one proton and no neutrons) surrounded by electrons.
(ROOT (S (NP (NNS Protons) (CC and) (NNS neutrons)) (VP (VBP are) (VP (VBN located) (PP (IN in) (NP (DT the) (JJ central) (NN nucleus))))) (. .)))