Question

Assign an oxidation state to each element or ion. (a) \(\mathrm{V}\) (b) \(\mathrm{Mg}^{2+}\) (c) \(\mathrm{Cr}^{3+}\) (d) \(\mathrm{O}_{2}\)

Short answer

(a) 0, (b) +2, (c) +3, (d) 0. Vanadium in elemental form and diatomic oxygen both have an oxidation state of 0, while the charges on the ions Mg2+ and Cr3+ indicate their respective oxidation states.

Step-by-step solution

Determining the Oxidation State of an Element in its Elemental Form

Elements in their elemental form always have an oxidation state of 0. This is because there are no more electronegative or electropositive elements present to alter its oxidation state.

Assigning Oxidation State to Monatomic Ions

For monatomic ions, the oxidation state is the same as the charge of the ion. This is due to the fact that the net charge results from the loss or gain of electrons compared to the neutral atom.

Assigning Oxidation State to Diatomic Molecules

In a diatomic molecule like oxygen gas, regardless of elemental or molecular forms, each atom has the same electronegativity, and therefore, they share electrons equally. In such cases, the oxidation state of each atom in the molecule is 0.

Key concepts

Chemistry Education

Understanding the essentials of chemistry is key for students tackling courses in science and engineering, but chemistry concepts can often seem complex. Simplifying these topics is crucial for effective learning. The concept of oxidation states, for example, might stymie students initially. Yet, with clear explanations and relatable examples, it becomes much more accessible.

When we discuss oxidation states, we talk about the apparent charge an atom would have if the compound was composed of ions. By building a strong foundation with such concepts, learners can better comprehend more intricate chemistry topics, laying the groundwork for success in their studies.

Redox Reactions

Redox reactions are a fundamental component of numerous biological and geological processes. They involve the transfer of electrons between two species, which can be seen as one species undergoing oxidation (losing electrons) and the other undergoing reduction (gaining electrons).

Understanding the underlying concepts of redox reactions, which revolve around the change in oxidation states, is crucial in grasping how these critical reactions occur. In essence, looking at the interaction between different elements and compounds through the lens of their oxidation states can reveal a lot about the chemical processes at play.

Oxidation Numbers

Assigning oxidation numbers is a way to keep track of electron transfers in chemical reactions. The oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. Consider it a bookkeeping tool used by chemists to analyze redox reactions more efficiently.

In our exercises:

• V (Vanadium) in its elemental form has an oxidation state of 0 since it's not combined with any other element.
• Mg²⁺ is a monatomic ion with an oxidation state of +2, showing it has lost two electrons.
• Cr³⁺ similarly has an oxidation state of +3.
• O₂, an oxygen molecule, consists of two oxygen atoms sharing electrons equally, thus each oxygen has an oxidation state of 0.

Mastering the assignment of oxidation states helps students predict the products of redox reactions and balance chemical equations, which is an invaluable skill in further chemistry studies.