( Anions ( ( may ( form ( where ( ( ( an atom ) ( with ( a ( ( nearly full ) ( outer ( shell gains ) ) ) ) ) ) electrons ) ) ) ) . ) )
(ROOT (S (NP (NNS Anions)) (VP (MD may) (VP (VB form) (SBAR (WHADVP (WRB where)) (S (NP (NP (DT an) (NN atom)) (PP (IN with) (NP (DT a) (ADJP (RB nearly) (JJ full)) (JJ outer) (NN shell) (NNS gains)))) (VP (VBZ electrons)))))) (. .)))
Anions may form where an atom with a nearly full outer shell gains electrons.
(ROOT (S (NP (NNS Anions)) (VP (VBP are) (VP (VBN formed) (PP (IN by) (NP (NP (NNS atoms)) (VP (VBG gaining) (NP (NNS electrons))))))) (. .)))