( ( ( The ( first ( two ( subatomic particles ) ) ) ) ( to ( be discovered ) ) ) ( ( were ( ( ( the electron ) and ) ( the ( atomic nucleus ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ first) (CD two) (JJ subatomic) (NNS particles)) (SBAR (S (VP (TO to) (VP (VB be) (VP (VBN discovered))))))) (VP (VBD were) (NP (NP (DT the) (NN electron)) (CC and) (NP (DT the) (JJ atomic) (NN nucleus)))) (. .)))
The first two subatomic particles to be discovered were the electron and the atomic nucleus .
(ROOT (S (NP (JJ Atomic) (NNS orbitals)) (VP (VBP are) (ADJP (VBN populated) (PP (IN with) (NP (NP (JJ subatomic) (NNS particles)) (VP (VBN known) (PP (IN as) (NP (NNS electrons)))))))) (. .)))