( Atoms ( ( ( have ( at ( their centre ) ) ) ( ( ( a nucleus ) , ) ( containing ( ( protons and ) neutrons ) ) ) ) . ) )
(ROOT (S (NP (NNS Atoms)) (VP (VBP have) (PP (IN at) (NP (PRP$ their) (NN centre))) (NP (NP (DT a) (NN nucleus)) (, ,) (VP (VBG containing) (NP (NNS protons) (CC and) (NNS neutrons))))) (. .)))
Atoms have at their centre a nucleus, containing protons and neutrons.
(ROOT (S (NP (NP (DT The) (NN atom)) (PP (IN in) (NP (DT a) (NN neutron)))) (VP (VBZ is) (VP (VBN found) (PP (IN in) (NP (DT the) (DT the) (NN nucleus))))) (. .)))