Give the oxidation state of the metal for each of the...

Give the oxidation state of the metal for each of the following oxides of the first transition series. (Hint: Oxides of formula $\mathrm{M}_{3} \mathrm{O}_{4}$ are examples of mixed valence compounds in which the metal ion is present in more than one oxidation state. It is possible to write these compound formulas in the equivalent format $\mathrm{MO} \cdot \mathrm{M}_{2} \mathrm{O}_{3}$, to permit estimation of the metal’s two oxidation states.) (a) $\mathrm{Sc}_{2} \mathrm{O}_{3}$ (b) $\mathrm{TiO}_{2}$ (c) $\mathrm{V}_{2} \mathrm{O}_{5}$ (d) $\mathrm{CrO}_{3}$ (e) $\mathrm{MnO}_{2}$ (f) $\mathrm{Fe}_{3} \mathrm{O}_{4}$ (g) $\mathrm{Co}_{3} \mathrm{O}_{4}$ (h) $\mathrm{NiO}$ (i) $\mathrm{Cu}_{2} \mathrm{O}$

Give the oxidation state of the metal for each of the following oxides of the first transition series. (Hint: Oxides of formula $\mathrm{M}_{3} \mathrm{O}_{4}$ are examples of mixed valence compounds in which the metal ion is present in more than one oxidation state. It is possible to write these compound formulas in the equivalent format $\mathrm{MO} \cdot \mathrm{M}_{2} \mathrm{O}_{3}$, to permit
estimation of the metal’s two oxidation states.)
(a) $\mathrm{Sc}_{2} \mathrm{O}_{3}$
(b) $\mathrm{TiO}_{2}$
(c) $\mathrm{V}_{2} \mathrm{O}_{5}$
(d) $\mathrm{CrO}_{3}$
(e) $\mathrm{MnO}_{2}$
(f) $\mathrm{Fe}_{3} \mathrm{O}_{4}$
(g) $\mathrm{Co}_{3} \mathrm{O}_{4}$
(h) $\mathrm{NiO}$
(i) $\mathrm{Cu}_{2} \mathrm{O}$

Key Concepts

Mixed Valence Compounds

Mixed valence compounds are those in which an element exists in more than one oxidation state within the same compound. This phenomenon is significant in the chemistry of transition metal oxides, where the presence of multiple oxidation states can influence the physical and chemical properties of the material. Conceptually, rewriting the formulas of such compounds into equivalent forms helps in the systematic determination of the individual oxidation states.

Stoichiometric Calculations in Oxidation State Determination

Stoichiometry involves using the quantitative relationships between the elements within a compound to determine unknown quantities. In the context of oxidation states, it involves setting up equations based on the known oxidation states of certain atoms (such as oxygen in oxides) and solving for the unknown oxidation state of the metal.

Transition Metal Chemistry

Transition metals often exhibit multiple oxidation states due to the involvement of d electrons in bonding. This flexibility leads to a diverse range of compounds, including oxides with different stoichiometric compositions. Understanding the electronic configuration and coordination environments of these metals is key to predicting and explaining their chemical behavior.

Oxidation State

The oxidation state is a number that represents the degree of oxidation of an element in a compound. It indicates the number of electrons an atom has gained or lost relative to its elemental form, and it is used to understand the electron distribution in a molecule. Determining oxidation states is essential for balancing redox equations and understanding chemical reactivity.

Charge Neutrality

This concept asserts that the sum of the oxidation states of all atoms in a compound must equal the overall charge of the compound. In neutral compounds, the sum must be zero. This principle is used to set up equations that allow the calculation of unknown oxidation numbers, particularly when dealing with compounds that contain varying oxidation states.

Transcript

Please give Ace some feedback