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The d-And-f-Block Elements

Short Answer Type

211.

Give Possible reason for the fact that the radii of Mn²⁺ ions of the first row transition metals. Ti²⁺ (Z = 22) to Cu²⁺ (Z = 29) decrease with increasing atomic number.

153 Views

212.

Explain the catalytic action of Fe(III) between the reaction of I^– and persulphate ion S₂O₈^2–.

141 Views

213. What is the reason of the greater tendency of transition metals to form complex compouds?

443 Views

214. Why the transition metals and their compounds are widely used as catalysts?

161 Views

215.
What can be inferred from the magnetic moment values of the following complex species?

Example

Magnetic Moment (BM)

K₄[Mn(CN)₆]

2.2

[Fe(H₂O)₆]²⁺

5.3

K₃ [Mn Cl₄]

5.9

Magnetic moment (μ) is given as:

μ = \sqrt{n (n + 2)} .

Where n is the number of unpaired electrons and M is magnetic moment is units of Bohr magneton (BM).

considering the value of (μ) equal to 1,2,3,4,5.
So we have the value,

$F o r v a l u e n = 1, μ = \sqrt{1 (1 + 2)} = \sqrt{3} = 1.732 F o r v a l u e n = 2, μ = \sqrt{2 (2 + 2)} = \sqrt{8} = 2.83 F o r v a l u e n = 3, μ = \sqrt{3 (3 + 2)} = \sqrt{15} = 3.87 F o r v a l u e n = 4, μ = \sqrt{4 (4 + 2)} = \sqrt{24} = 4.899 F o r v a l u e n = 5, μ = \sqrt{5 (5 + 2)} = \sqrt{35} = 5.92$

(ii)

\sqrt{n (n + 2)} = 53

n = 1, d^{2} {sp}^{3}, {CN}^{-} is a strong ligand . n = 4, {sp}^{2} d^{2}, H_{2} O is a weak ligand .

(iii)

\sqrt{n (n + 2)} = 5.9

(i) K₄[Mn(CN)₆]

For in transition metals, the magnetic moment is calculated from the spin-only formula. Therefore,

$\sqrt{n (n + 2)} = 2.2$

We can see from the above calculation that the given value is closest to n = 1. Also, in this complex, Mn is in the +2 oxidation state. This means that Mn has 5 electrons in the d-orbital.

Hence, we can say that CN - is a strong field ligand that causes the pairing of electrons.

(ii) [Fe(H2O)6]²⁺

$\sqrt{n (n + 2)} = 5.3$

We can see from the above calculation that the given value is closest to n = 4. Also, in this complex, Fe is in the +2 oxidation state. This means that Fe has 6 electrons in the d-orbital.

Hence, we can say that H2O is a weak field ligand and does not cause the pairing of electrons.

(iii) K2[MnCl4]

$\sqrt{n (n + 2)} = 5.9$

We can see from the above calculation that the given value is closest to n = 5. Also, in this complex, Mn is in the +2 oxidation state. This means that Mn has 5 electrons in the d-orbital.

Hence, we can say that Cl - is a weak field ligand and does not cause the pairing of electrons.

450 Views

216. What are interstitial compounds? What are their main characteristics?

197 Views

217.

Explain the structures of dichromate and chromate ion.

409 Views

Long Answer Type

218. Both d-block and p-block elements exhibit variable oxidation state. Give reasons for the difference in there variations.

535 Views

Short Answer Type

219.

Why are transition metal fluorides ionic in nature, whereas bromides and chlorides are covalent in nature.

255 Views

220.

Why are the ionization enthalpies of 5d elements greater than those of 3d and 4d elements?

1242 Views

Example	Magnetic Moment (BM)
K₄[Mn(CN)₆]	2.2
[Fe(H₂O)₆]²⁺	5.3
K₃ [Mn Cl₄]	5.9

Previous Year Papers

Test Series

Test Yourself

Short Answer Type

215. What can be inferred from the magnetic moment values of the following complex species? Example Magnetic Moment (BM) K4[Mn(CN)6] 2.2 [Fe(H2O)6]2+ 5.3 K3 [Mn Cl4] 5.9

Long Answer Type

Short Answer Type

215.
What can be inferred from the magnetic moment values of the following complex species?

Example

Magnetic Moment (BM)

K₄[Mn(CN)₆]

2.2

[Fe(H₂O)₆]²⁺

5.3

K₃ [Mn Cl₄]

5.9