( ( ( neutron -- ) ( ( a ( subatomic particle ) ) ( of ( ( nearly ( the ( same mass ) ) ) ( ( ( as ( the proton ) ) but ) ( with ( no ( electric charge ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NN neutron)) (: --) (NP (NP (DT a) (JJ subatomic) (NN particle)) (PP (IN of) (NP (NP (RB nearly) (DT the) (JJ same) (NN mass)) (PP (PP (IN as) (NP (DT the) (NN proton))) (CC but) (PP (IN with) (NP (DT no) (JJ electric) (NN charge))))))) (. .)))
neutron -- a subatomic particle of nearly the same mass as the proton but with no electric charge.
(ROOT (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NNS neutrons)))) (VP (MD can) (VP (VB vary) (PP (IN between) (NP (NP (NNS atoms)) (PP (IN of) (NP (DT the) (JJ same) (NN element))))))) (. .)))