( ( Be ( able ( to ( distinguish ( ( ( ( elements , ) ( molecular compounds ) ) and ) ( ion compounds ) ) ) ) ) ) . )
(ROOT (S (VP (VB Be) (ADJP (JJ able) (S (VP (TO to) (VP (VB distinguish) (NP (NP (NNS elements)) (, ,) (NP (JJ molecular) (NNS compounds)) (CC and) (NP (NN ion) (NNS compounds)))))))) (. .)))
Be able to distinguish elements, molecular compounds and ion compounds.
(ROOT (S (NP (DT A) (JJ binary) (JJ molecular) (NN compound)) (VP (VBZ is) (VP (VBN made) (PRT (RP up)) (PP (IN of) (NP (CD two) (NNS elements))))) (. .)))