( Radioactivity ( ( is ( ( ( ( the ( spontaneous disintegration ) ) ( of ( an ( unstable ( atomic nucleus ) ) ) ) ) and ) ( ( the emission ) ( of ( ( particles or ) ( electromagnetic radiation ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Radioactivity)) (VP (VBZ is) (NP (NP (NP (DT the) (JJ spontaneous) (NN disintegration)) (PP (IN of) (NP (DT an) (JJ unstable) (JJ atomic) (NN nucleus)))) (CC and) (NP (NP (DT the) (NN emission)) (PP (IN of) (NP (NP (NNS particles)) (CC or) (NP (JJ electromagnetic) (NN radiation))))))) (. .)))
Radioactivity is the spontaneous disintegration of an unstable atomic nucleus and the emission of particles or electromagnetic radiation.
(ROOT (S (NP (NNP Radioactivity)) (VP (VP (VBZ is) (NP (NP (DT the) (NN release)) (PP (IN of) (NP (NNS particles))))) (CC and/or) (VP (NP (NN energy)) (PP (IN from) (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (DT an) (NN atom))))))) (. .)))