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प्रश्न
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:
Atomic sizes
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उत्तर
- Generally, ions or atoms of the same charge in a series show a gradual decrease in radius with increasing atomic number, although this decrease is very small.
- In the same respective vertical column (group), the size of the atoms of the 4d series is larger than that of the corresponding elements of the 3d series. However, the size of the corresponding elements of the 5d series is almost the same as that of the 4d series.
- The reason for this nearly identical size between 4d and 5d series elements is Lanthanoid Contraction, which cancels out the expected increase in size due to the addition of a new shell.
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संबंधित प्रश्न
Account for the following:
Cu+2 salts are coloured, while Zn2+ salts are white.
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
What can be inferred from the magnetic moment value of the following complex species?
| Example | Magnetic Moment (BM) |
| K2[MnCl4] | 5.9 |
Give reasons: Sc3+ is colourless in aqueous solution whereas Ti3+ is coloured.
Account for the following :
Ti4+ is colourless whereas V4+ is coloured in an aqueous solutions.
Explain why Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)
The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr3+ ion is ______.
Why EΘ values for Mn, Ni and Zn are more negative than expected?
Out of \[\ce{Cu2Cl2}\] and \[\ce{CuCl2}\], which is more stable and why?
When a brown compound of manganese (A) is treated with \[\ce{HCl}\] it gives a gas (B). The gas taken in excess, reacts with \[\ce{NH3}\] to give an explosive compound (C). Identify compounds A, B and C.
The halides of transition elements become more covalent with increasing oxidation state of the metal. Why?
Answer the following question:
Which element of the first transition series has highest second ionisation enthalpy?
Which of the following ions will exhibit colour in aqueous solution?
Why is the `"E"_(("V"^(3+)//"V"^(2+)))^"o"` value for vanadium comparatively low?
Which one among the following metals of the 3d series has the lowest melting point?
Which of the following transition metals shows +1 and +2 oxidation states?
A transition element X has an electronic configuration [Ar]4s23d3. Predict its likely oxidation states.
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.
Why are interstitial compounds well known for transition metals?
