(a) Complete the following chemical reaction equations : (i) MnO_(4(aq))^(-) + C_(2)O_(4(aq))^(2-) + H_((aq))^(+) to (ii) Cr_(2) O_(7 (aq))^(2-) + Fe_((aq))^(2+) + H_((aq))^(+) to (b) Explain the following observations about the transition/inner transition elements : (i) There is in general an increase in density of element from titanium (Z = 22) to copper ( Z= 29). (ii) There occurs much more frequent metal-metal bonding in compounds of heavy transition elements (3^(rd) series). (iii) The members in the actinoid series exhibit a larger number of oxidation states than the corresponding members in the lanthanoid series.

(a) Complete the following chemical reaction equations : (i) MnO_(4(a

1.	(a) Complete the following chemical reaction equations : (i) MnO_(4(aq))^(-) + C_(2)O_(4(aq))^(2-) + H_((aq))^(+) to (ii) Cr_(2) O_(7 (aq))^(2-) + Fe_((aq))^(2+) + H_((aq))^(+) to (b) Explain the following observations about the transition/inner transition elements : (i) There is in general an increase in density of element from titanium (Z = 22) to copper ( Z= 29). (ii) There occurs much more frequent metal-metal bonding in compounds of heavy transition elements (3^(rd) series). (iii) The members in the actinoid series exhibit a larger number of oxidation states than the corresponding members in the lanthanoid series.
Answer» Solution :(i) `5 C_(2)O_(4)^(2-) + 2Mn O_(4)^(-) + 16 H^(+) to 2Mn^(2+) + 8H_(2)O + 10 CO_(2)` (ii) `Cr_(2)O_(7)^(2-) + 6FE^(2+) + 14 H^(+) to 2Cr^(3+) + 6 Fe^(3+) + 7H_(2)O` (b) (i) As we move along a transition series from left to right (i.e. Ti to Cu) , the atomic radii decrease due to increase in nuclear charge . Hence the atomic volume decreases. At the same time , atomic mass increases. Hence the density from TITANIUM (Ti) to Copper (Cu) increases. (ii) Since `3^(rd)` series of transition elements show the variable oxidation state . (iii) Actinoids series show a large number of oxidation state due to very small energy gap between 5f , 6 d and 7s subsells.