Skip to main content
Ch.21 - Transition Elements and Coordination Chemistry
Chapter 21, Problem 55

The highest oxidation state for the early transition metals Sc, Ti, V, Cr, and Mn is the periodic group number. The highest oxidation state for the later transition elements Fe, Co, and Ni is less than the periodic group number. Explain.

Verified step by step guidance
1
<insert step 1> The oxidation state of an element is determined by the number of electrons it can lose, gain, or share when forming chemical compounds. For transition metals, this is often related to the number of d-electrons available for bonding.
<insert step 2> Early transition metals like Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), and Manganese (Mn) have fewer d-electrons and are located in the first half of the transition metal series. They can achieve their highest oxidation states by using all their valence electrons, including s and d electrons, which corresponds to their group number.
<insert step 3> For example, Manganese (Mn) is in group 7 and can exhibit an oxidation state of +7, as seen in permanganate ion (MnO4^-).
<insert step 4> Later transition metals like Iron (Fe), Cobalt (Co), and Nickel (Ni) have more d-electrons and are located in the second half of the transition metal series. The d-electrons are more tightly bound and less available for bonding, resulting in lower maximum oxidation states than their group number.
<insert step 5> For instance, Iron (Fe) is in group 8 but typically exhibits a maximum oxidation state of +6, as seen in ferrate ion (FeO4^2-), which is less than its group number. This is due to the increased stability of lower oxidation states and the involvement of d-electrons in bonding.

Verified Solution

Video duration:
0m:0s
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

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

Oxidation States

Oxidation states indicate the degree of oxidation of an atom in a compound, reflecting the number of electrons lost or gained. For transition metals, these states can vary widely due to their ability to lose different numbers of d and s electrons. The highest oxidation state often corresponds to the group number in the periodic table, particularly for early transition metals, which can utilize all available valence electrons.
Recommended video:
Guided course
02:42
Oxidation Numbers

Transition Metals

Transition metals are elements found in groups 3 to 12 of the periodic table, characterized by their ability to form variable oxidation states and complex ions. Early transition metals, such as Sc, Ti, V, Cr, and Mn, can achieve higher oxidation states due to their electronic configuration, allowing them to lose more electrons. In contrast, later transition metals like Fe, Co, and Ni typically exhibit lower oxidation states due to increased stability in their electron configurations.
Recommended video:
Guided course
03:12
Transition Metals

Periodic Trends

Periodic trends refer to the predictable patterns observed in the properties of elements as one moves across or down the periodic table. The group number often correlates with the maximum oxidation state for early transition metals, while later transition metals show a deviation from this trend. This is due to factors such as effective nuclear charge and electron shielding, which influence the ability of these metals to lose electrons and form higher oxidation states.
Recommended video:
Guided course
00:38
Periodic Trends