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Ch.23 - Transition Metals and Coordination Chemistry
All textbooksBrown 15th EditionCh.23 - Transition Metals and Coordination ChemistryProblem 12
Chapter 23, Problem 12

Complete the exercises below. Which periodic trend is partially responsible for the observation that the maximum oxidation state of the transition-metal elements peaks near groups 7B and 8B? a. The number of valence electrons reaches a maximum at group 8B. b. The effective nuclear charge increases on moving right across each period. c. The radii of the transition-metal elements reach a minimum for group 8B, and as the size of the atoms decreases it becomes easier to remove electrons.

Verified step by step guidance
1
Step 1: Understand the periodic trends involved in the problem. The periodic table shows trends in properties such as atomic radius, ionization energy, and effective nuclear charge as you move across a period or down a group.
Step 2: Consider the trend of the number of valence electrons. In transition metals, the number of valence electrons generally increases as you move from left to right across a period, reaching a maximum at group 8B.
Step 3: Analyze the effective nuclear charge trend. As you move across a period from left to right, the effective nuclear charge experienced by the valence electrons increases, which can affect the ability of an atom to lose or gain electrons.
Step 4: Examine the trend in atomic radii. The atomic radius generally decreases across a period due to the increasing effective nuclear charge, which pulls the electron cloud closer to the nucleus.
Step 5: Relate these trends to the oxidation states of transition metals. The maximum oxidation state of transition metals is influenced by the number of valence electrons and the effective nuclear charge, which affects the ease of electron removal. Consider how these factors peak around groups 7B and 8B.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Oxidation States of Transition Metals

The oxidation state of an element refers to the charge it would have if all bonds to atoms of different elements were fully ionic. Transition metals can exhibit multiple oxidation states due to their ability to lose different numbers of d and s electrons. The maximum oxidation state often correlates with the number of valence electrons available for bonding, which is particularly relevant in groups 7B and 8B.
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Effective Nuclear Charge

Effective nuclear charge (Z_eff) is the net positive charge experienced by an electron in a multi-electron atom. As you move across a period in the periodic table, Z_eff increases due to the addition of protons in the nucleus without a corresponding increase in shielding from inner electrons. This increase in Z_eff enhances the attraction between the nucleus and the valence electrons, influencing the oxidation states of transition metals.
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Periodic Trends in Atomic Radius

Atomic radius generally decreases across a period due to increasing nuclear charge, which pulls electrons closer to the nucleus. In transition metals, this trend affects the ease of electron removal; as the atomic radius decreases, it becomes energetically more favorable to remove electrons, thereby influencing the maximum oxidation states observed in groups 7B and 8B.
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Related Practice
Textbook Question

Four-coordinate metals can have either a tetrahedral or a square-planar geometry; both possibilities are shown here for [PtCl2(NH3)2].

a. What is the name of this molecule?

b. Would the tetrahedral molecule have a geometric isomer?

c. Would the tetrahedral molecule be diamagnetic or paramagnetic?

d. Would the square-planar molecule have a geometric isomer?

Textbook Question

Which of these crystal-field splitting diagrams represents:

a. a weak-field octahedral complex of Fe³⁺ ,

b. a strong-field octahedral complex of Fe³⁺ 

c. a tetrahedral complex of Fe³⁺

d. a tetrahedral complex of Ni²⁺ (The diagrams do not indicate the relative magnitudes of ∆. ) [Find more in Section 23.6.]

Textbook Question

In the linear crystal-field shown here, the negative charges are on the z-axis. Using Figure 23.28 as a guide, predict which of the following choices most accurately describes the splitting of the d orbitals in a linear crystal-field? [Find more in Section 23.6.]                                                                                                                                                

Textbook Question

Write out the ground-state electron configurations of b. Ru²⁺

Textbook Question

Write out the ground-state electron configurations of  c. Au³⁺ ,