The d & f Block Elements Chemistry - The d & f Block Elements

Explain giving reason:

Transition metals and their many compounds act as good catalyst.

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 points:
Ionisation enthalpies.

Explain giving reason:
Transition metals and many of their compounds show paramagnetic behaviour.

What is meant by ‘disproportionation’? Give two examples of disproportionation reaction in aqueous solution.

Give examples and suggest reasons for the following features of the transition metal chemistry:

The highest oxidation state is exhibited in oxoanions of a metal.

Lanthanum, gadolinium and lutetium are extraordinarily stable in +3 oxidation state. Explain.
(Atomic number: La = 57, Gd = 64, Lu = 71)

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 points:

Electronic configurations:

Indicate the steps in the preparation of:
KMnO₄ from pyrolusite ore.

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

Example	Magnatic Moment (BM)
K4[Mn(CN)6]	2.2
[Fe(H2O)6]2+	5.3
K2[MnCl4]	5.9

What are alloys? Name an important alloy which contains some of the lanthanoid metals. Mention its uses.

Write down the electronic configuration of:
Th⁴⁺

Write down the electronic configuration of:

Lu²⁺

Write down the electronic configuration of:

Pm³⁺

Describe the oxidising action of potassium dichromate and write the ionic equations for its reaction with:
Iodide

Read the passage given below and answer the following questions:

Transition elements are elements that have partially filled d-orbitals. The configuration of these elements corresponds to (n - 1)d^1-10ns^1-2. It is important to note that the elements mercury, cadmium and zinc are not considered transition elements because of their electronic configurations, which corresponds to (n - 1)d¹⁰ns². Some general properties of transition elements are:

These elements can fonn coloured compounds and ions due to d-d transition;

These elements exhibit many oxidation states;

A large variety of ligands can bind themselves to these elements, due to this, a wide variety of stable complexes formed by these ions. The boiling and melting point of these elements are high. These elements have a large ratio of charge to the radius.

In these questions (Q. No. i-iv), a statement of assertion followed by a statement ofreason is given. Choose the correct answer out of the following choices.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

1. Assertion: Tungsten has very high melting point.

Reason: Tungsten is a covalent compound.

2. Assertion: Zn, Cd and Hg are normally not considered transition metals.

Reason: d-Orbitals in Zn, Cd and Hg elements are completely filled, hence these metals do not show the general characteristics properties of the transition elements.

3. Assertion: Copper metal gets readily corroded in acidic aqueous solution such as HCl and dil. H₂SO₄.

Reason: Free energy change for this process is positive.

4. Assertion: Tailing of mercury occurs on passing ozone through it.

Reason: Due to oxidation of mercury.

5. Assertion: Transition metals are poor reducing agents.

Reason: Transition metals fonn numerous alloys with other metals.

Read the passage given below and answer the following questions:
The f-block elements are those in which the differentiating electron enters the (n -2)f orbital. There are two series of F-block elements corresponding to filling of 4f and 5f-orbitals. The series of 4f-orbitals is called lanthanides. Lanthanides show different oxidation states depending upon stability of f⁰, f⁷ and F¹⁴ configurations, though the most conunon oxidation states is +3. There is a regular decrease in size oflanthanides ions with increase in atomic number which is known as lanthanide contraction.
The following questions are multiple choice questions. Choose the most appropriate answer:

1. The atomic numbers of three lanthanide elements X, Y and Z are 65, 68 and 70 respectively, their Ln³⁺ electronic configuration is:

1. 4f⁸, 4f¹¹, 4f¹³
2. 4f¹¹, 4f⁸, 4f¹³
3. 4f⁰, 4f², 4f¹¹
4. 4f³, 4f⁷, 4f⁹

2. Lanthanide contraction is observed in:

1. Gd
2. At
3. Xe
4. Te

3. Which of the following is not the configuration oflanthanoid?

1. [Xe]4f¹⁰6s²
2. [Xe]4f¹5d¹6s²
3. [Xe]4d¹⁴5d¹⁰6s²
4. [Xe]4f⁷5d¹6s²

4. Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.

1. Cerium (Z = 58)
2. Europium (Z = 63)
3. Lanthanum (Z = 57)
4. Gadolinium (Z = 64

5. Identify the incorrect statement among the following.

1. Lanthanoid contraction is the accumulation of successive shrinkages.
2. The different radii of Zr and Hf due to consequence of the lanthanoid contraction.
3. Shielding power of 4f electrons is quite weak.
4. There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.

Read the passage given below and answer the following questions:
The transition elements have incompletely filled d-subshells in their ground state or in any of their oxidation states. The transition elements occupy position in betweens- and p-blocks in groups 3-12 of the Periodic table. Starting from fourth period, transition elements consists of four complete series : Sc to Zn, Y to Cd and La, Hf to Hg and Ac, Rf to Cn. In general, the electronic configuration of outer orbitals of these elements is (n - 1)d^1-10 n^1-2. The electronic configurations of outer orbitals of Zn, Cd, Hg and Cn are represented by the general formula (n - 1)d¹⁰ns². All the transition elements have typical metallic properties such as high tensile strength, ductility, malleability. Except mercury, which is liquid at room temperature, other transition elements have typical metallic structures. The transition metals and their compounds also exhibit catalytic property and paramagnetic behaviour. Transition metal also forms alloys. An alloy is a blend of metals prepared by mixing the components. Alloys may be homogeneous solid solutions in which the atoms of one metal are distributed randomly among the atoms of the other.
The following questions are multiple choice questions. Choose the most appropriate answer:

1. Which of the following characteristics of transition metals is associated with higher catalytic activity?

1. High enthalpy of atomisation.
2. Variable oxidation states.
3. Paramagnetic behaviour.
4. Colour of hydrated ions.

2. Transition elements form alloys easily because they have.

1. Same atomic number.
2. Same electronic configuration.
3. Nearly same atomic size.
4. Same oxidation states.

3. The electronic configuration of tantalum (Ta) is:

1. [Xe]4f⁰5d¹6s²
2. [Xe]4f¹⁴5d²6s²
3. [Xe]4f¹⁴5d³6s²
4. [Xe]4f¹⁴5d⁴6s²

4. Which one of the following outer orbital configurations may exhibit the largest number of oxidation states?

1. 3d⁵4s¹
2. 3d⁵4s²
3. 3d²4s²
4. 3d³4s²

5. The correct statement(s) among the following is/ are:

1. All d and f-block elements are metals.
2. All d and f-block elements form coloured ions.
3. All d and f-block elements are paramagnetic.

1. (I) only
2. (I) and (II) only
3. (II) and (III) only
4. (I), (II) and (III)

The adsorption of hydrogen by platinum black is called:

Gallium is in __________ state at room temperature.

Which one of the following statements about lanthanides is false ?