( ( ( ( ( ( ( An ( even number ) ) ( ( ( of protons ) or ) ( of neutrons ) ) ) ( are ( ( ( more stable ) ( -LRB- ( ( higher ( binding energy ) ) -RRB- ) ) ) ( because ( of ( pairing effects ) ) ) ) ) ) , ) so ) ( ( even-even nuclei ) ( are ( ( much ( more stable ) ) ( than odd-odd ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT An) (JJ even) (NN number)) (PP (PP (IN of) (NP (NNS protons))) (CC or) (PP (IN of) (NP (NNS neutrons))))) (VP (VBP are) (ADJP (ADJP (ADJP (RBR more) (JJ stable)) (PRN (-LRB- -LRB-) (NP (NP (JJR higher)) (NP (JJ binding) (NN energy))) (-RRB- -RRB-))) (PP (RB because) (IN of) (NP (VBG pairing) (NNS effects)))))) (, ,) (IN so) (S (NP (JJ even-even) (NNS nuclei)) (VP (VBP are) (ADJP (ADJP (RB much) (RBR more) (JJ stable)) (PP (IN than) (ADJP (JJ odd-odd)))))) (. .)))
An even number of protons or of neutrons are more stable (higher binding energy) because of pairing effects, so even-even nuclei are much more stable than odd-odd.
(ROOT (S (NP (NP (NNP Nuclei)) (PP (IN with) (NP (NP (RB even) (NNS numbers)) (PP (IN of) (NP (NP (NNS protons)) (, ,) (NP (NNS neutrons)) (, ,) (CC or) (NP (DT both))))))) (VP (VBP are) (ADJP (RBR more) (JJ likely) (S (VP (TO to) (VP (VB be) (ADJP (JJ stable))))))) (. .)))