( ( Remember ( that ( ions ( are ( atoms ( that ( have ( ( ( gained or ) lost ) electrons ) ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Remember) (SBAR (IN that) (S (NP (NNS ions)) (VP (VBP are) (NP (NP (NNS atoms)) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (VP (VBN gained) (CC or) (VBN lost) (NP (NNS electrons))))))))))) (. .)))
Remember that ions are atoms that have gained or lost electrons.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT an) (NN atom)) (VP (VBZ gains) (CC or) (VBZ loses) (NP (DT an) (NN electron))))) (NP (PRP it)) (VP (VBZ becames) (NP (DT a) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN ion))) (. .)))