( ( An ion ) ( ( is ( ( a ( charged particle ) ) ( formed ( when ( ( ( a ( neutral ( ( atom or ) group ) ) ) ( of atoms ) ) ( ( ( gain or ) lose ) ( one ( or ( more electrons ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT An) (NN ion)) (VP (VBZ is) (NP (NP (DT a) (JJ charged) (NN particle)) (VP (VBN formed) (SBAR (WHADVP (WRB when)) (S (NP (NP (DT a) (JJ neutral) (NN atom) (CC or) (NN group)) (PP (IN of) (NP (NNS atoms)))) (VP (VB gain) (CC or) (VB lose) (NP (CD one) (CC or) (JJR more) (NNS electrons)))))))) (. .)))
An ion is a charged particle formed when a neutral atom or group of atoms gain or lose one or more electrons.
(ROOT (S (NP (DT Some) (NNS atoms)) (VP (VBP are) (ADJP (ADJP (RBR more) (JJ stable)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VB gain) (CC or) (VB lose) (NP (DT an) (NN electron) (CC and) (NN form) (NNS ions))))))) (. .)))