( ( Label ( ( ( ( ( ( ( ( a proton ) , ) ( a neutron ) ) , ) ( an electron ) ) , ) and ) ( ( the nucleus ) ( of ( the atom ) ) ) ) ) . )
(ROOT (S (VP (VB Label) (NP (NP (DT a) (NN proton)) (, ,) (NP (DT a) (NN neutron)) (, ,) (NP (DT an) (NN electron)) (, ,) (CC and) (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (DT the) (NN atom)))))) (. .)))
Label a proton, a neutron, an electron, and the nucleus of the atom.
(ROOT (S (NP (NP (DT The) (NN atom)) (PP (IN in) (NP (DT a) (NN neutron)))) (VP (VBZ is) (VP (VBN found) (PP (IN in) (NP (DT the) (DT the) (NN nucleus))))) (. .)))