Question

Name the ions with three charges that have the following electron configurations: (a) [Ar]3d^{3} , ( b ) \text { [Ar], } (c) \([\mathrm{Kr}] 4 d^{6}\) (d) \([\operatorname{Xe}] 4 f^{14} 5 d^{6}\)

Short answer

(a) ext{V}^{3+}, (b) ext{Sc}^{3+}, (c) ext{Rh}^{3+}, (d) ext{Ir}^{3+}

Step-by-step solution

Understanding Electron Configuration

Electron configurations show the distribution of electrons of an atom in atomic orbitals. Identifying ions and their charges involves understanding how many electrons are gained or lost compared to the neutral atom.

Electron Configuration for (a): [Ar]3d^3

The configuration [Ar]3d^3 corresponds to Vanadium (V) in its +3 oxidation state. Vanadium (V) normally has a configuration of [Ar]3d^34s^2; losing 3 electrons renders it [Ar]3d^3.

Identifying the Ion for (a) [Ar]3d^3

This is the configuration of Vanadium (III) ion, ext{V}^{3+}.

Electron Configuration for (b): [Ar]

When an ion has an electron configuration of [Ar], it has the same electron configuration as the element Argon. This usually means the ion originally had a greater atomic number but has lost its outer electrons to achieve stability. For example, this is achieved by the Calcium ion, ext{Ca}^{2+}.

Identifying the Ion for (b) [Ar]

Ironically, no ion typically exists with a +3 charge to yield an [Ar] configuration directly. However, the ion ext{Sc}^{3+} achieves an ext{empty} 3d and 4s configuration which resembles [Ar] from losing 3 electrons.

Electron Configuration for (c): [Kr]4d^6

This corresponds to Rhodium (Rh), which in a neutral state has the configuration [Kr]4d^85s^1. The loss of 3 electrons to form a +3 charge results in [Kr]4d^6.

Identifying the Ion for (c) [Kr]4d^6

This is the configuration of Rhodium (III) ion, ext{Rh}^{3+}.

Electron Configuration for (d): [Xe]4f^{14}5d^6

Iridium (Ir), in its neutral state, has the configuration [Xe]4f^{14}5d^76s^2. The loss of 3 electrons (usually the 6s and 5d) results in the configuration [Xe]4f^{14}5d^6.

Identifying the Ion for (d) [Xe]4f^{14}5d^6

This matches the configuration of Iridium (III) ion, ext{Ir}^{3+}.

Key concepts

Ions

Ions are atoms or molecules that have lost or gained one or more electrons, resulting in a net electrical charge. Unlike neutral atoms, ions have either a positive or negative charge, depending on the balance of protons and electrons.
In the context of electron configuration, identifying ions involves understanding how many electrons an element needs to lose or gain to achieve a stable electron configuration. The process of losing electrons leads to a positive ion, known as a cation, while gaining electrons results in a negative ion, called an anion.

For example:

• The Vanadium ion (V³⁺) has lost three electrons to achieve the configuration [Ar]3d³, becoming a positively charged ion.
• The Calcium ion (Ca²⁺) achieves a stable configuration similar to [Ar] by losing two electrons.

Oxidation States

Oxidation states, often referred to as oxidation numbers, are used primarily to indicate the degree of oxidation of an atom in a chemical compound. It essentially represents the number of electrons lost or gained by an atom.
Understanding oxidation states helps in explaining why certain elements form specific ions. The concept also aids in determining the electron configuration of an ion. For instance, transition metals often have multiple oxidation states due to their variable electron configurations.

For example:

• Vanadium can exist in multiple oxidation states, but in the +3 state, it has lost three electrons, leading to the electron configuration [Ar]3d³.
• Similarly, Iridium in the +3 oxidation state loses three electrons, resulting in the configuration [Xe]4f¹⁴5d⁶.

Transition Metals

Transition metals are a group of elements found in the d-block of the periodic table. These metals are known for their ability to form various stable ions due to the different oxidation states they can achieve.
Transition metals have partially filled d orbitals, which makes their electron configurations more complex and allows for multiple ways of losing and gaining electrons.

Key characteristics include:

• They often exhibit multiple oxidation states, as seen in elements like Rhodium and Vanadium.
• Many are colored or form colored compounds due to d-d electron transitions.
• They can form stable complexes with ligands, contributing to their versatility in chemical reactions.

The presence of d sublevels influences their chemistry significantly, allowing for rich reactivity patterns and forming a variety of compounds with unique properties.

Electron Distribution

Electron distribution refers to the arrangement of electrons around the nucleus of an atom. Understanding electron distribution is crucial in predicting and explaining the chemical behavior of elements.
Electrons are distributed across different energy levels and sublevels, filling up in the sequence dictated by the Aufbau principle. In ions, this distribution can change significantly from the element's neutral state when electrons are gained or lost.

For instance:

• The electron configuration [Ar]3d³ indicates that Vanadium (V) has lost electrons from its 4s and partially from its 3d orbitals to achieve that distribution when it forms a V³⁺ ion.
• Iridium (Ir) achieves [Xe]4f¹⁴5d⁶ by losing its 6s and some 5d electrons in its +3 oxidation state, demonstrating how electron distribution changes in ionic states.

Correct understanding of electron distribution helps in identifying ionic forms and understanding the reactivity and stability of elements and compounds.