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प्रश्न
Why do transition elements show variable oxidation states ? In 3d series (Sc to Zn), which elements shows the maximum number of oxidation state and why ?
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उत्तर
Transition elements have an incomplete set of d-orbitals in their penultimate shell. They have their valence electrons in (n−1)d- and ns-orbitals. Since there is very little energy difference between these orbitals, electrons from both the energy levels can be used for bond formation. As a result, transition elements exhibit variable oxidation states.
Valence shell electronic configuration for Mn (Z = 25): 3d5 4s2
In the 3d series, Mn has the maximum number of unpaired electrons present in the d-subshell (5 electrons). Hence, Mn exhibits the maximum number of oxidation states, ranging from +2 to +7.
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संबंधित प्रश्न
What are the transition elements? Write two characteristics of the transition elements.
Account for the following:
Cu+ ion is unstable in aqueous solution.
NF3 is possible, but NF5 is not. Why?
Following are the transition metal ions of 3d series:
Ti4+, V2+, Mn3+, Cr3+
(Atomic numbers: Ti = 22, V = 23, Mn = 25, Cr = 24)
Answer the following:
1) Which ion is most stable in an aqueous solution and why?
2) Which ion is a strong oxidising agent and why?
3) Which ion is colourless and why?
Account for the following :
Ti4+ is colourless whereas V4+ is coloured in an aqueous solutions.
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
While filling up of electrons in the atomic orbitals, the 4s orbital is filled before the 3d orbital but reverse happens during the ionisation of the atom. Explain why?
Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:
(activation energy, Threshold energy, increased, lowered, partially, full, d-d transition, Benzoic acid, benzaldehyde)
Only those transition metal ions will be coloured which have ______ filled d-orbitals facilitating ______.
Passing H2S gas into a mixture of Mn2+ and Ni2+, Cu2+, ions in an acidified aqueous solution precipitates.
How is the variability in oxidation states of transition metals different from that of p-block elements?
