Advertisements
Advertisements
Question
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:
Oxidation states
Advertisements
Solution 1
Elements in the same horizontal group generally show the same number of oxidation states. The number of oxidation states shown by elements in the middle of each series is maximum, while those at the end are minimum.
Solution 2
Elements have varying oxidation states in both series. The highest oxidation state corresponds to the total amount of electrons in ‘s’ and ‘d’ orbitals. The 5d transition series shows fewer oxidation states than the 4d series. In the 3d series, +2 and +3 oxidation states are common, resulting in stable complexes. In other series, OsO4 and PtF6 are stable at higher oxidation states.
APPEARS IN
RELATED QUESTIONS
How would you account for the following: Transition metals form complex compounds.
Give reasons:
Transition metals show variable oxidation states.
Out of Mn3+ and Cr3+, which is more paramagnetic and why ?
(Atomic nos. : Mn = 25, Cr = 24)
Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?
Which is a stronger reducing agent, Cr2+ or Fe2+ and why?
How would you account for the following:
Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.
Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?
What are alloys?
Why do transition metal ions possess a great tendency to form complexes?
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 ?
When \[\ce{KMnO4}\] solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because ______.
Explain why does colour of KMnO4 disappear when oxalic acid is added to its solution in acidic medium.
Match the solutions given in Column I and the colours given in Column II.
| Column I (Aqueous solution of salt) |
Column II (Colour) |
| (i) \[\ce{FeSO2.7H2O}\] | (a) Green |
| (ii) \[\ce{NiCl2.4H2O}\] | (b) Light pink |
| (iii) \[\ce{MnCl2.4H2O}\] | (c) Blue |
| (iv) \[\ce{CoC12,6H2O}\] | (d) Pale green |
| (v) \[\ce{Cu2 Cl2}\] | (e) Pink |
| (f) Colourless |
Assertion (A): Cu cannot liberate hydrogen from acids.
Reason (R): Because it has positive electrode potential.
Passing H2S gas into a mixture of Mn2+ and Ni2+, Cu2+, ions in an acidified aqueous solution precipitates.
Which of the following ions will exhibit colour in aqueous solution?
Why are all copper halides known except that copper iodide?
Consider the following standard electrode potential values:
\[\ce{Sn^{2+}_{ (aq)} + 2e^- -> Sn_{(s)}}\]; E0 = −0.14 V
\[\ce{Fe^{3+}_{ (aq)} + e^- -> Fe^{2+}_{ (aq)}}\]; E0 = +0.77 V
What is the cell reaction and potential for the spontaneous reaction that occurs?
Account for the following:
Copper has an exceptionally positive `"E"_("M"^(2+)//"M")^0` value.
