( ( ( ( ( ( The number ) ( of ( neutrons ( in ( the nucleus ) ) ) ) ) ( can vary ) ) and ) ( we ( call ( atoms ( of ( ( one element ) ( that ( have ( ( different numbers ) ( of ( ( neutrons , ) ( isotopes ( of ( that element ) ) ) ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN number)) (PP (IN of) (NP (NP (NNS neutrons)) (PP (IN in) (NP (DT the) (NN nucleus)))))) (VP (MD can) (VP (VB vary)))) (CC and) (S (NP (PRP we)) (VP (VBP call) (NP (NP (NNS atoms)) (PP (IN of) (NP (NP (CD one) (NN element)) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (NP (NP (JJ different) (NNS numbers)) (PP (IN of) (NP (NP (NNS neutrons)) (, ,) (NP (NP (NNS isotopes)) (PP (IN of) (NP (DT that) (NN element))))))))))))))) (. .)))
The number of neutrons in the nucleus can vary and we call atoms of one element that have different numbers of neutrons, isotopes of that element.
(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))))))) (. .)))