( ( Atoms ( that ( introduce ( ( energy levels ) ( capable ( of ( accepting ( a ( valence electron ) ) ) ) ) ) ) ) ) ( ( are ( termed acceptors ) ) . ) )
(ROOT (S (NP (NP (NNS Atoms)) (SBAR (WHNP (WDT that)) (S (VP (VB introduce) (S (NP (NN energy) (NNS levels)) (ADJP (JJ capable) (PP (IN of) (S (VP (VBG accepting) (NP (DT a) (JJ valence) (NN electron))))))))))) (VP (VBP are) (VP (VBN termed) (NP (NNS acceptors)))) (. .)))
Atoms that introduce energy levels capable of accepting a valence electron are termed acceptors.
(ROOT (S (NP (NP (NNS Electrons)) (PP (IN in) (NP (NP (DT the) (JJ outer) (NN energy) (NN level)) (PP (IN of) (NP (DT an) (NN atom)))))) (VP (VBP are) (VP (VBN called) (NP (JJ valence) (NNS electrons)))) (. .)))