The catalytic activity of transition metals and their compounds is ascribed mainly to (Mains 2012)

Diamagnetic ion contains all paired electrons while ions which contain unpaired electrons are known as paramagnetic in nature. The valence shell electronic configuration for lanthanide ions is as follows, For ytterbium, 2 4 CrO D and F Block Elements 31 2+ 14 Yb = Xe 4f , 2+ Yb ion contains all paired electrons. It is a diamagnetic ion. For cerium, 2+ 2 Ce = Xe 4f , For samarium, 2+ 6 Sm = Xe 4f , For Europium, 2+ 7 Eu = Xe 4f , In 2+ Eu ion all electrons are unpaired. It is paramagnetic. Thus, (a) is the correct option. 26. KMnO4 can be pr