Short Answer TypeHow would you account for the following?
(i) Transition metals exhibit variable oxidation states.
(ii) Zr (Z = 40) and Hf (Z = 72) have almost identical radii.
(iii) Transition metals and their compounds act as catalystName the two groups into which phenomenon of catalysis can be divided. Give an example of each group with the chemical equation involved.
Explain the following giving an appropriate reason in each case.
O2 and F2 both stabilise higher oxidation states of metals but O2 exceeds F2 in doing so.
Explain the following giving an appropriate reason in each case.
Structures of Xenon fluorides cannot be explained by Valence Bond approach.
According to the valence bond approach, covalent bonds are formed by the overlapping of the half-filled atomic orbital. But xenon has a fully filled electronic configuration. Hence the structure of xenon fluorides cannot be explained by VBT.
For example: In case of XeF2
Hybridization is:
Total, valence electron =8 for Xe
Monovalent atom F=2
So, total hybrid orbitals =1/2 [valence electron + monovalent atom + cation + anion] as no cation and anion so term is zero
So hybrid orbital are ½[8+2+0+0] = 5
So hybridization = sp3d
According to sp3d hybridization, the structure should be Trigonal bipyramidal, but the actual structure is linear. So, VBT fails to answer this however VSPER theory explains the liner shape.
How would you account for the following?
i) Many of the transition elements are known to form interstitial compounds.
ii)The metallic radii of the third (5d) series of transition metals are virtually the same as those of the corresponding group member of the second (4d) series.
iii) Lanthanoids from primarily +3 ions, while the actinoids usually have higher oxidation states in their compounds, +4 or even + 6 being typical.
Assign reasons for the following:
(i) Copper (I) ion is not known in aqueous solution.
(ii) Actinoids exhibit greater range of oxidation states than Lanthanoids.
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