The correct order of the spin-only magnetic moment of metal ions in the following low spin complexes, [V(CN)6]4−,[Fe(CN)6]4−,[Ru(NH3)6]3+, and [Cr(NH3)6]2+, is :
Solution:- (A)V2+>Cr2+>Ru3+>Fe2+ According to equations, all the complexes are low spin. No. of Complex Configuration unpaired electrons [[V(CN)6]4−t2g3eg03 No. ot Complex Configuration unpaired electrons [V(CN)6]4−t2g3eg0 3 [Cr(NH)3)6]2+t2g4eg0 2 [Ru(NH3)6]3+t2g5eg0 1 [Fe(CN)6]4−t2g6eg0 0
Multiple oxidation states- The oxidation states of d block elements show very few energy gaps; therefore, they exhibit many oxidation states. Also, the energy difference between s and d orbital is very less. Therefore both the electrons are involved in ionic and covalent bond formation, which ultimately leads to multiple oxidation states.
Formation of complex compounds- Ligands show a binding behavior and can form so many stable complexes with the help of transition metals. This property is mainly due to:
Availability of vacant d orbitals.
Comparatively small sizes of metals.
Hardness- Transition elements are tough and have high densities because of the presence of unpaired electrons.
Melting and boiling points- Melting and boiling points of transition are very high because of the presence of unpaired electrons and partially filled d orbitals. They form strong bonds and have high melting and boiling points.
Atomic radii- The atomic and ionic radius of the transition elements decreases as we move from Group 3 to group 6. However, it remains the same between group 7 and group 10, and from group 11 to group 12 increases.
Ionization enthalpy- The ionization enthalpies of the transition elements are generally on the greater side as compared to the S block elements