( ( The ( valence electrons ) ) ( ( ( ( are ( in ( ( ( ( ( the outer ) -LRB- ) highest ) -RRB- ) ( energy levels ) ) ) ) and ) ( are ( ( the ( main determiners ) ) ( of ( chemical ( ( activity and ) bonding ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ valence) (NNS electrons)) (VP (VP (VBP are) (PP (IN in) (NP (NP (NP (DT the) (JJ outer)) (-LRB- -LRB-) (NP (JJS highest)) (-RRB- -RRB-)) (NP (NN energy) (NNS levels))))) (CC and) (VP (VBP are) (NP (NP (DT the) (JJ main) (NNS determiners)) (PP (IN of) (NP (NN chemical) (NN activity) (CC and) (NN bonding)))))) (. .)))
The valence electrons are in the outer (highest) energy levels and are the main determiners of chemical activity and bonding.
(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)))) (. .)))