Question

Determine the highest possible oxidation state for each element. $${ a. } \ V \quad \text { b. } \operatorname{Re} \quad \text { c. } \operatorname{Pd}$$

Short answer

The highest oxidation states are: a. Vanadium (V) +5, b. Rhenium (Re) +7, c. Palladium (Pd) +4.

Step-by-step solution

Determining Oxidation States for Vanadium (V)

The highest possible oxidation state for an element is typically equal to the number of valence electrons it can use for bonding. For vanadium (V), which is in Group 5 of the periodic table, the highest common oxidation state corresponds to its group number, which is +5, demonstrating the loss of its 5 valence electrons.

Determining Oxidation States for Rhenium (Re)

Rhenium (Re) is in Group 7 of the periodic table. The highest oxidation state it can achieve is +7, involving the loss of all seven valence electrons.

Determining Oxidation States for Palladium (Pd)

Palladium (Pd) is in Group 10 of the periodic table. However, despite being in the 10th group, its highest oxidation state is +4. This is because palladium is a transition metal, and the maximum oxidation state it commonly achieves is the number of electrons in its outermost s and d orbitals, which totals 4 for palladium (2 from s and 2 from the first half of the d orbitals).

Key concepts

Valence Electrons

Valence electrons are the outermost electrons of an atom and are paramount in determining an element's chemical properties and its ability to participate in bonding. Imagine them like friends to an element that it can give away or share with others to create stable relationships, which in the world of chemistry are bonds. For instance, in the oxidation states problem, vanadium (V) has 5 valence electrons because it is in Group 5 of the periodic table, hence it can achieve an oxidation state of +5 by 'giving away' all these electrons. Similarly, rhenium (Re) can achieve a +7 state by losing its 7 valence electrons.
Understanding how to count valence electrons is crucial as they play a key role in bonding and chemical reactions. Elements in the same group in the periodic table have the same number of valence electrons, which means their chemical behavior will have similarities. However, when it comes to transition metals like palladium (Pd), valence electrons include those in both the outermost s and d orbitals, adding a layer of complexity to predicting their behavior.

Periodic Table Groups

The periodic table is structured in such a way that elements are arranged in columns known as 'groups' that share similar properties due to their similar valence electron configurations. There are 18 groups in total. For instance, all elements in Group 1 (also known as alkali metals) have one valence electron and exhibit similar reactivity and bonding characteristics.
Generally, the group number can help predict the highest oxidation state for the main group elements, as it usually equals the number of valence electrons available for bonding. However, teachers often point out that there are exceptions to this rule, especially with heavier elements or those undergoing complex chemistry, like transition metals. Therefore, caution should be exercised when using this generalization for predicting chemical behavior or oxidation states. It's an initial guide, not an absolute law.

Transition Metals

Transition metals are a group of elements found in the center of the periodic table, encompassing groups 3 through 12. They are characterized by the presence of electrons in d orbitals. These elements are particularly fascinating because they often exhibit multiple oxidation states. Unlike the main group elements, their highest oxidation states are not always apparent from the group number.
This is exemplified by palladium (Pd) from Group 10. You would expect it to have a highest oxidation state of +10, yet its actual highest state is +4. This is because palladium, like other transition metals, achieves its oxidation states through the involvement of both s and partially filled d orbitals. Consequently, understanding these metals requires a comprehensive look at their electron configurations and how they can be manipulated during bonding. Transition metals' chemistry is rich and complex, offering a diverse palette of possibilities in compound formation and industrial applications.