( ( Carbon 14 ) ( ( ( is radioactive ) ( because ( , ( ( as ( ( other atoms ) ( with ( ( the ( wrong percentage ) ) ( of ( neutrons ( to protons ) ) ) ) ) ) ) ( , ( it ( is unstable ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Carbon) (CD 14)) (VP (VBZ is) (ADJP (JJ radioactive)) (SBAR (IN because) (S (, ,) (PP (IN as) (NP (NP (JJ other) (NNS atoms)) (PP (IN with) (NP (NP (DT the) (JJ wrong) (NN percentage)) (PP (IN of) (NP (NP (NNS neutrons)) (PP (TO to) (NP (NNS protons))))))))) (, ,) (NP (PRP it)) (VP (VBZ is) (ADJP (JJ unstable)))))) (. .)))
Carbon 14 is radioactive because, as other atoms with the wrong percentage of neutrons to protons, it is unstable.
(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.