Problem 43 - Chemistry

Question

What tripositive ion has the electron configuration \([\mathrm{Kr}] 4 d^{3} ?\) What neutral atom has the electron configuration \([\mathrm{Kr}] 5 s^{2} 4 d^{2} ?\)

Step-by-Step Solution

Answer

The tripositive ion is Ru³⁺ and the neutral atom is Zr.

Step 1: Understanding Electron Configurations

The electron configuration \([Kr] 4d^3\) for the tripositive ion implies that when the atom loses 3 electrons, this is its configuration. We need to find the neutral atom that when it loses 3 electrons, has this configuration.

Step 2: Finding the Neutral Atom for the Tripositive Ion

Given the ion's configuration \([Kr] 4d^3\), this results from a neutral atom that had 6 electrons in the 4d orbital. Therefore, the neutral atom's configuration would have been \([Kr] 4d^6\), which corresponds to the element Ruthenium (Ru). Thus, the tripositive ion is \( ext{Ru}^{3+}\).

Step 3: Understanding the Second Electron Configuration

The second electron configuration \([Kr] 5s^2 4d^2\) is for a neutral atom. We need to identify which element corresponds to this configuration.

Step 4: Finding the Neutral Atom

The given configuration \([Kr] 5s^2 4d^2\) corresponds to the element with two electrons in the 4d subshell and two electrons in the 5s subshell. Counting from Krypton (Kr) which is atomic number 36, the additional 4 electrons lead you to Zr, Zirconium, with atomic number 40.

Key Concepts

Electron Configuration of Ions

When atoms become ions, they either lose or gain electrons. This process alters their electron configurations. For positive ions, also known as cations, electrons are removed. Conversely, negative ions, or anions, gain electrons. The electron configuration that results from this change dictates many properties of the ion.

• A common example of this is the aluminum ion, \(\text{Al}^{3+}\), which has lost three electrons from a neutral aluminum atom.
• This results in an electron configuration of \([\text{Ne}] 3s^2 3p^1\) for the neutral atom, becoming \([\text{Ne}]\) in the ion after losing three electrons.

Understanding these adjustments helps in predicting the chemical behaviors of ions, as losing or gaining electrons changes the charge and electron interactions within the ion.

Neutral Atom Electron Configuration

The electron configuration of a neutral atom defines its arrangement of electrons in distinct energy levels, and shells, around the nucleus. Every element on the periodic table has a unique electron configuration.

• This configuration reflects the element's number of electrons, which equals the atomic number.
• Examples include hydrogen with one electron: \( 1s^1 \), and oxygen with eight electrons: \( 1s^2 2s^2 2p^4 \).

A neutral zirconium atom, \([\text{Kr}] 5s^2 4d^2\), has an atomic number of 40, meaning it has 40 electrons filling its subshells according to energy levels. This stacking behavior of electrons is crucial for element identification and emphasizes the foundational principles of chemical reactivity.

Ruthenium Ion

Ruthenium, a transition metal, holds intriguing properties with its electron configurations, particularly noticeable in its ions. The neutral electron configuration for ruthenium is \([\text{Kr}] 5s^1 4d^7\). As Ruthenium loses three electrons to form the tripositive ion \(\text{Ru}^{3+}\), its configuration becomes \([\text{Kr}] 4d^5\). Here's why this is relevant:

• Understanding this configuration is key for identifying the chemical properties of ruthenium ions, like catalytic activity.
• The electron removal\( \text{-} \)specifically from the highest energy subshells like 5s and 4d\( \text{-} \)reduces electron-electron repulsions within the atom.

These ion configurations offer insights into predicting the stability and type of chemical bonds that Ruthenium can form.

Zirconium

Zirconium, noted for being a transition metal, is used in various applications owing to its durability and corrosion resistance. The neutral atom's electron configuration \([\text{Kr}] 5s^2 4d^2\) imparts unique qualities. Here’s some crucial information about zirconium.

• As a neutral atom, zirconium holds an atomic number of 40, placing it locally on the periodic table right after Krypton (Kr).
• Its electron configuration confers characteristic traits like refractory properties and ability to withstand heat and chemical exposure.

Appreciating the electronic structure of zirconium equips students with an understanding of its potential reactivity and role in materials science and engineering.

Electron Subshell Configuration

Subshell configuration provides a detailed picture of how electrons are distributed among different subshells (s, p, d, f) within an atom. Each subshell accommodates a specific number of electrons and is characterized by different energy levels.

• For instance, the s subshell can hold up to 2 electrons, while the p subshell can hold 6.
• This rule governs the electron buildup across the periodic table and influences chemical bonding.

The iron atom, for example, has an electron configuration of \([\text{Ar}] 3d^6 4s^2\), showing how electrons fill subshells subsequent to their energy levels. Grasping these configurations is essential for comprehending why some elements form specific types of bonds and experience chemical reactions, facilitating deeper insights into material sciences and elemental properties.