( ( ( ( ( ( ( The ( atomic nuclei ) ) ( of these ) ) ( ( isotopes all ) ( contain ( ( ( 6 protons ) , ) ( which ( ( defines them ) ( as carbon ) ) ) ) ) ) ) , ) but ) ( they ( ( ( ( ( have ( ( ( ( 6 , ) 7 ) and ) ( 8 neutrons ) ) ) , ) respectively ) , ) ( which ( ( gives them ) ( different masses ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (JJ atomic) (NN nuclei)) (PP (IN of) (NP (DT these)))) (VP (VBZ isotopes) (RB all) (VP (VB contain) (NP (NP (CD 6) (NNS protons)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ defines) (NP (PRP them)) (PP (IN as) (NP (NN carbon)))))))))) (, ,) (CC but) (S (NP (PRP they)) (VP (VBP have) (NP (NP (CD 6)) (, ,) (NP (CD 7)) (CC and) (NP (CD 8) (NNS neutrons))) (, ,) (ADVP (RB respectively)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ gives) (NP (PRP them)) (NP (JJ different) (NNS masses))))))) (. .)))
The atomic nuclei of these isotopes all contain 6 protons, which defines them as carbon, but they have 6, 7 and 8 neutrons, respectively, which gives them different masses.
(ROOT (S (NP (NP (DT A) (NN carbon) (NN atom)) (PP (IN with) (NP (NP (CD 6) (NNS protons)) (CC and) (NP (CD 8) (NNS neutrons))))) (VP (VBZ is) (ADVP (RBR more) (RB specifically)) (VP (VBN known) (PP (IN as) (NP (NN carbon) (CD 14))))) (. .)))
A carbon atom with 6 protons and 8 neutrons is more specifically known as carbon 14.