( ( ( ( ( Carbon 12 ) , ) ( the ( stable form ) ) ) , ) ( ( has ( ( ( 6 protons ) and ) ( 6 neutrons ) ) ) . ) )
(ROOT (S (NP (NP (NNP Carbon) (CD 12)) (, ,) (NP (DT the) (JJ stable) (NN form)) (, ,)) (VP (VBZ has) (NP (NP (CD 6) (NNS protons)) (CC and) (NP (CD 6) (NNS neutrons)))) (. .)))
Carbon 12, the stable form, has 6 protons and 6 neutrons.
(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.