( ( When ( Schr&ouml;dinger ( studied ( the atom ) ) ) ) ( , ( he ( ( ( ( ( abandoned ( ( the idea ) ( of ( precise orbits ) ) ) ) , ) and ) ( ( replaced them ) ( with ( ( a description ) ( of ( ( the regions ) ( of ( ( space , ) ( which ( he ( called ( ( orbitals , ) ( where ( ( the electrons ) ( were ( most ( likely ( to ( be found ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNP Schr&ouml;dinger)) (VP (VBD studied) (NP (DT the) (NN atom))))) (, ,) (NP (PRP he)) (VP (VP (VBD abandoned) (NP (NP (DT the) (NN idea)) (PP (IN of) (NP (JJ precise) (NNS orbits))))) (, ,) (CC and) (VP (VBD replaced) (NP (PRP them)) (PP (IN with) (NP (NP (DT a) (NN description)) (PP (IN of) (NP (NP (DT the) (NNS regions)) (PP (IN of) (NP (NP (NN space)) (, ,) (SBAR (WHNP (WDT which)) (S (NP (PRP he)) (VP (VBD called) (NP (NP (NNS orbitals)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NNS electrons)) (VP (VBD were) (ADJP (RBS most) (JJ likely) (S (VP (TO to) (VP (VB be) (VP (VBN found))))))))))))))))))))) (. .)))
When Schr&ouml;dinger studied the atom, he abandoned the idea of precise orbits, and replaced them with a description of the regions of space, which he called orbitals, where the electrons were most likely to be found.
(ROOT (S (NP (DT The) (NN orbital)) (VP (VBZ is) (NP (NP (DT the) (NN area)) (SBAR (WHADVP (WRB where)) (S (NP (DT an) (NN electron)) (VP (VBZ is) (ADJP (RBS most) (JJ likely) (S (VP (TO to) (VP (VB be) (VP (VBN found))))))))))) (. .)))