Advertisements
Advertisements
प्रश्न
Why first ionisation enthalpy of Cr is lower than that of Zn?
Advertisements
उत्तर
The electronic configuration of chromium and zinc are respectively:
\[\ce{Cr (24) = [Ar] 3d^5 4s^2}\]
\[\ce{Zn (30) = [Ar] 3d^10 4s^2}\]
It is easy to remove electron from 4s1-orbital (unpaired) rather than from 4s2-orbital (paired).
APPEARS IN
संबंधित प्रश्न
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?
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:
Electronic configurations
How would you account for the following?
Zr (Z = 40) and Hf (Z = 72) have almost identical radii.
Complete and balance the following chemical equations
`Fe^(2+) + MnO_4^(-) + H^+ ->`
The paramagnetic character in the 3d-transition series elements increases up to Mn and then decreases.
How is potassium dichromate prepared from chrome iron ore?
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
Which is the most stable oxidation state of iron?
In lake test for Al3+ ions, there is the formation of coloured ‘floating lake’. It is due to ______.
When acidified \[\ce{K2Cr2O7}\] solution is added to \[\ce{Sn^{2+}}\] salts then \[\ce{Sn^{2+}}\] changes to ______.
Why does copper not replace hydrogen from acids?
Reactivity of transition elements decreases almost regularly from Sc to Cu. Explain.
Assertion: The highest oxidation state of osmium is +8.
Reason: Osmium is a 5d-block element.
Identify A to E and also explain the reactions involved.
The product of oxidation of I– with \[\ce{MnO^{-}4}\] in alkaline medium is:-
Which of the following ions acts as a typical transition metal ion?
The compounds of \[\ce{Ti^4+}\] ions are colourless due to ______.
Give a reason for the following:
Zinc, cadmium and mercury are considered as d-block elements but not regarded as transition elements.
For M2+/M and M3+/M2+systems, the EΘ values for some metals are as follows:
| Cr2+/Cr | −0.9 V |
| Mn2+/Mn | −1.2 V |
| Fe2+/Fe | −0.4 V |
| Cr3/Cr2+ | −0.4 V |
| Mn3+/Mn2+ | +1.5 V |
| Fe3+/Fe2+ | +0.8 V |
Use this data to comment upon:
The ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.
