( ( ( The energy ) ( required ( to ( ( remove ( an electron ) ) ( from ( its ( neutral ( orbital ( to ( form ( a cation ) ) ) ) ) ) ) ) ) ) ) ( ( is ( ( ( the ( ionization energy ) ) and ) ( ( the energy ) ( ( ( given up ) ( by ( an atom ) ) ) ( in ( forming ( ( an anion ) ( is ( ( called electron ) affinity ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN energy)) (VP (VBN required) (S (VP (TO to) (VP (VB remove) (NP (DT an) (NN electron)) (PP (IN from) (NP (PRP$ its) (JJ neutral) (NN orbital) (S (VP (TO to) (VP (VB form) (NP (DT a) (NN cation)))))))))))) (VP (VBZ is) (NP (NP (DT the) (NN ionization) (NN energy)) (CC and) (NP (NP (DT the) (NN energy)) (VP (VBN given) (PRT (RP up)) (PP (IN by) (NP (DT an) (NN atom))) (PP (IN in) (S (VP (VBG forming) (SBAR (S (NP (DT an) (NN anion)) (VP (VBZ is) (VP (VBN called) (NP (NN electron)) (ADVP (RB affinity))))))))))))) (. .)))
The energy required to remove an electron from its neutral orbital to form a cation is the ionization energy and the energy given up by an atom in forming an anion is called electron affinity .
(ROOT (S (NP (NNS Anions)) (VP (VBP are) (VP (VBN formed) (PP (IN by) (NP (NP (NNS atoms)) (VP (VBG gaining) (NP (NNS electrons))))))) (. .)))