question_answer 75)

    Which of the following lanthanoids show +2 oxidation state besides the characteristic oxidation state +3 of lanthanoids? (a) Ce                                    (b) Eu             (c) Yb                                     (d) Ho

Answer:

                    (b, c) Cerium (Z = 57) =» Electronic configuration = Oxidation state of Ce = +3, +4 (b) Europium (Z = 63) Þ Electronic configuration = Oxidation state of Eu =+2, +3                                 (c) Ytterbium (Z= 70) ^Electronic configuration = Oxidation state of Yb = +2, +3 (d) Holmium( Z=67) Þ Electronic configuration = Oxidation state of Ho = +3