Explain giving reasons :
Transition metals and many of their compounds show paramagnetic behaviour.
The enthalpies of atomisation of the transition metals are high.
The transition metals generally form coloured compounds.
Transition metals and their many compounds act as good catalyst.
Explain giving reasons :
Transition metals and many of their compounds show paramagnetic behaviour.
The enthalpies of atomisation of the transition metals are high.
The transition metals generally form coloured compounds.
Transition metals and their many compounds act as good catalyst.
Transition elements have unpaired electrons. Each unpaired electron has a magnetic moment associated with its spin angular momentum and orbital angular momentum. This is the reason for paramagnetism in transition metals.
Transition elements have high effective nuclear charge and a large number of valence electrons (unpaired electrons in their atoms. Therefore, they form very strong metallic bonds. These atoms have strong interatomic interaction, as a result, the enthalpy of atomization of transition metals is high.
Formation of coloured compounds by transition metals is due to partial adsorption of visible light. The electron absorbs the radiation of a particular frequency (of the visible region) and jumps Into next orbital.
Catalysts, at the solid surface, involve the formation of bonds between reactants molecules and atoms of the surface of the catalyst (I row transition metals utilize 3d and 4s-electrons for bonding). This has the effect of increasing the concentration of the reactants at the catalyst surface and also lowering of the activation energy.
The catalytic activity of the transition elements can be explained by two basic facts.
(a) Owing to their ability to show variable oxidation states and form complexes, transition metals form unstable intermediate compounds. Thus, they provide a new path with the lower activation energy, Ea, for the reaction.
(b) Transition metals also provide a suitable surface for the reactions to occur.
Transition metal ions show variable oxidation states, so they are effective catalysts, e.g.,
Reaction 2I−+S2O2−8Fe3+−−−→I2+2SO2−4
Mechanism of catalysing action of Fe3+ in the above reaction
(a) 2Fe3++2I−→2Fe2++I2
(b) 2Fe2++S2O2−8→2Fe3++2SO2−4
Transition elements have unpaired electrons. Each unpaired electron has a magnetic moment associated with its spin angular momentum and orbital angular momentum. This is the reason for paramagnetism in transition metals.
Transition elements have high effective nuclear charge and a large number of valence electrons (unpaired electrons in their atoms. Therefore, they form very strong metallic bonds. These atoms have strong interatomic interaction, as a result, the enthalpy of atomization of transition metals is high.
Formation of coloured compounds by transition metals is due to partial adsorption of visible light. The electron absorbs the radiation of a particular frequency (of the visible region) and jumps Into next orbital.
Catalysts, at the solid surface, involve the formation of bonds between reactants molecules and atoms of the surface of the catalyst (I row transition metals utilize 3d and 4s-electrons for bonding). This has the effect of increasing the concentration of the reactants at the catalyst surface and also lowering of the activation energy.
The catalytic activity of the transition elements can be explained by two basic facts.
(a) Owing to their ability to show variable oxidation states and form complexes, transition metals form unstable intermediate compounds. Thus, they provide a new path with the lower activation energy, Ea, for the reaction.
(b) Transition metals also provide a suitable surface for the reactions to occur.
Transition metal ions show variable oxidation states, so they are effective catalysts, e.g.,
Reaction 2I−+S2O2−8Fe3+−−−→I2+2SO2−4
Mechanism of catalysing action of Fe3+ in the above reaction
(a) 2Fe3++2I−→2Fe2++I2
(b) 2Fe2++S2O2−8→2Fe3++2SO2−4
