( ( When ( ( the ( last level ) ) ( ( does not ) ( ( fill completely ) ( with electrons ) ) ) ) ) ( , ( ( the atom ) ( ( is ( considered ( ( chemically reactive ) ( which ( creates ( the ( ability ( to ( ( link easily ) ( with ( ( other atoms ) ( ( ( ( ( The electrons ) ( in ( the ( outermost level ) ) ) ) ( are ( called ( the ( valence electrons ) ) ) ) ) and ) ( they ( control ( ( the ( chemical bonding ) ) ( of ( the atom ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (JJ last) (NN level)) (VP (VBZ does) (RB not) (VP (VB fill) (ADVP (RB completely)) (PP (IN with) (NP (NNS electrons))))))) (, ,) (NP (DT the) (NN atom)) (VP (VBZ is) (VP (VBN considered) (NP (NP (JJ chemically) (NN reactive)) (SBAR (WHNP (WDT which)) (S (VP (VBZ creates) (NP (DT the) (NN ability) (S (VP (TO to) (VP (VB link) (ADVP (RB easily)) (PP (IN with) (NP (NP (JJ other) (NNS atoms)) (SBAR (S (S (NP (NP (DT The) (NNS electrons)) (PP (IN in) (NP (DT the) (JJ outermost) (NN level)))) (VP (VBP are) (VP (VBN called) (NP (DT the) (JJ valence) (NNS electrons))))) (CC and) (S (NP (PRP they)) (VP (VBP control) (NP (NP (DT the) (JJ chemical) (NN bonding)) (PP (IN of) (NP (DT the) (NN atom)))))))))))))))))))) (. .)))
When the last level does not fill completely with electrons, the atom is considered chemically reactive which creates the ability to link easily with other atoms The electrons in the outermost level are called the valence electrons and they control the chemical bonding of the atom.
(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)))) (. .)))