( ( ( ( ( ( ( The number ) ( of ( neutrons ( a ( specific element ) ) ) ) ) ( has ( can vary ) ) ) , ) but ) ( ( as ( long ( as ( ( ( the number ) ( of protons ) ) ( is ( the same ) ) ) ) ) ) ( it ( ( ( is ( the ( same element ) ) ) and ) ( has ( the ( same ( chemical properties ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NP (NNS neutrons)) (NP (DT a) (JJ specific) (NN element))))) (VP (VBZ has) (VP (MD can) (VP (VB vary))))) (, ,) (CC but) (S (ADVP (RB as) (RB long) (SBAR (IN as) (S (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NNS protons)))) (VP (VBZ is) (NP (DT the) (JJ same)))))) (NP (PRP it)) (VP (VP (VBZ is) (NP (DT the) (JJ same) (NN element))) (CC and) (VP (VBZ has) (NP (DT the) (JJ same) (NN chemical) (NNS properties))))) (. .)))
The number of neutrons a specific element has can vary, but as long as the number of protons is the same it is the same element and has the same chemical properties.
(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))))))) (. .)))