Chapter 4: The d-and f-Block Elements

Chemistry Part 1 • Class 12

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Chapter Analysis

Advanced28 pages • English

Quick Summary

This chapter explores the d-and f-block elements of the periodic table, focusing on the electronic configurations, general characteristics, and trends in properties such as oxidation states and atomic sizes. A significant emphasis is placed on the transition metals and their complex behavior due to incomplete d-orbitals, as well as the unique chemistry of inner transition metals like lanthanoids and actinoids. The chapter also discusses the practical applications of these elements and their compounds, notably in industries as catalysts and for their roles in advancing human technologies.

Key Topics

  • Electronic configurations of d and f-block elements
  • Oxidation states of transition elements
  • Lanthanoid and actinoid chemistry
  • Complex formation and stability
  • Catalytic properties of transition metals
  • Lanthanoid contraction
  • Applications of d- and f-block elements

Learning Objectives

  • Identify the position of d- and f-block elements in the periodic table.
  • Explain the electronic configurations of transition and inner transition elements.
  • Evaluate the stability of oxidation states using electrode potential values.
  • Understand the preparation and properties of compounds like K2Cr2O7 and KMnO4.
  • Compare lanthanoids and actinoids concerning their electronic configurations and chemical reactivity.

Questions in Chapter

Write down the electronic configuration of:

Answer: Cr3+, Cu+, Co2+, Mn2+, Pm3+, Ce4+, Lu2+, Th4+

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Why are Mn2+ compounds more stable than Fe2+ towards oxidation to their +3 state?

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Explain briefly how +2 state becomes more and more stable in the first half of the first row transition elements with increasing atomic number?

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To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements?

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What may be the stable oxidation state of the transition element with the following d electron configurations in the ground state of their atoms: 3d3, 3d5, 3d8 and 3d4?

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Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.

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What is lanthanoid contraction? What are the consequences of lanthanoid contraction?

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What are the characteristics of the transition elements and why are they called transition elements? Which of the d-block elements may not be regarded as the transition elements?

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In what way is the electronic configuration of the transition elements different from that of the non transition elements?

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What are the different oxidation states exhibited by the lanthanoids?

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Explain giving reasons why transition metals and many of their compounds show paramagnetic behaviour.

Answer: The presence of unpaired d-electrons leads to paramagnetic behavior.

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Additional Practice Questions

What factors contribute to the high melting and boiling points of transition metals?

medium

Answer: The high melting and boiling points are due to the involvement of (n-1)d electrons in addition to ns electrons in metallic bonding, leading to strong interatomic interactions.

How does the electronic configuration relate to the catalytic properties of transition metals?

hard

Answer: Transition metals can use their d and s orbitals to form variable oxidation states that facilitate redox reactions, thus enabling them to act as catalysts.

Describe the impact of lanthanoid contraction on the periodic properties of successive elements.

medium

Answer: Lanthanoid contraction leads to smaller than expected sizes of subsequent elements, affecting their chemical reactivity and separation processes.

What is the role of transition metals in biological systems?

medium

Answer: Transition metals like iron and copper play crucial roles in biological systems, such as oxygen transport and electron transfer in enzymatic processes.

Compare the stability of different oxidation states in lanthanoids and actinoids.

hard

Answer: Lanthanoids exhibit a consistent +3 oxidation state due to their electronic configuration, while actinoids show variability due to their 5f orbitals, leading to multiple oxidation states.