Question

What element has the following ground-state electron configuration: \([\mathrm{Ar}] 4 \mathrm{s}^{2} 3 \mathrm{d}^{6}\) ? (Chapter 5\()\)

Short answer

The element with the given ground-state electron configuration \([\mathrm{Ar}] 4 \mathrm{s}^{2} 3 \mathrm{d}^{6}\) is Iron (Fe).

Step-by-step solution

Determine the electron configuration of Argon

Argon is a noble gas, and its electron configuration is: \(1 \mathrm{s}^{2} 2 \mathrm{s}^{2} 2 \mathrm{p}^{6} 3 \mathrm{s}^{2} 3 \mathrm{p}^{6}\). The simplified notation for Argon in the provided electron configuration is \([\mathrm{Ar}]\).

Add the given extra electrons

We need to add the given extra electrons (\(4 \mathrm{s}^{2}\) and \(3 \mathrm{d}^{6}\)) to Argon's electron configuration: \([\mathrm{Ar}] 4 \mathrm{s}^{2} 3 \mathrm{d}^{6}\).

Identify the element

After adding the extra electrons, the full electron configuration is: \(1 \mathrm{s}^{2} 2 \mathrm{s}^{2} 2 \mathrm{p}^{6} 3 \mathrm{s}^{2} 3 \mathrm{p}^{6} 4 \mathrm{s}^{2} 3 \mathrm{d}^{6}\). Now count the total number of electrons: \(2 + 2 + 6 + 2 + 6 + 2 + 6 = 26\). The element with 26 electrons is Iron (Fe). So, the element with the given ground-state electron configuration is Iron (Fe).

Key concepts

The Periodic Table and Electron Configuration

The periodic table is not only a chart to display elements; it also provides crucial insights into the structure of atoms. It is organized into periods (rows) and groups (columns), with each element having a unique position based on its atomic number. When examining an element's electron configuration, the periodic table can serve as a map.

For instance, the configuration \(\mathrm{[Ar]} 4\mathrm{s}^2 3\mathrm{d}^6\) directly tells us that we're dealing with an element in the fourth period (due to the presence of a 4s orbital) and in one of the groups where the d-block elements are found. Therefore, by navigating the periodic table with this understanding, it becomes much easier to recognize that the element in question is iron (Fe), as it sits in the 4th period and is the 6th element in the d-block, pairing up with the information provided by the electron configuration.

Understanding Atomic Structure through Electron Configuration

Atomic structure is central to understanding the properties and behavior of elements. At the core of atomic structure is the electron configuration, which maps out the distribution of electrons within an atom. Electrons occupy regions around the nucleus called orbitals, with each orbital having a set capacity. The most stable electron configuration is achieved when electrons populate orbitals in a way that minimizes repulsion and maximizes stability.

This concept explains why iron's electron configuration, \(\mathrm{[Ar]} 4\mathrm{s}^2 3\mathrm{d}^6\), is organized as it is. Electrons are added to the lowest energy orbitals first, following Hund's rule and the Aufbau principle. Thus, the 4s orbital is filled prior to the 3d orbitals, despite the seemingly out-of-order numbering. Understanding these rules helps us grasp why certain configurations exist and how they contribute to the chemical properties of an element.

Chemical Elements and Their Unique Electron Configurations

Each chemical element has a unique electron configuration that is fundamental to its chemical characteristics. Electrons are arranged in shells, subshells, and orbitals with increasing energy levels. When identifying an element, like in the exercise where we sought the element with the electron configuration \(\mathrm{[Ar]} 4\mathrm{s}^2 3\mathrm{d}^6\), we're really looking at a 'fingerprint' indicative of iron (Fe).

The uniqueness of each element's electron configuration means that just by knowing the number of electrons in an atom and how they are arranged can tell us a great deal about the element's chemical behavior. In Iron's case, possessing six electrons in the 3d subshell contributes to its magnetic properties and its ability to form various oxidation states. Understanding electron configurations is thus a powerful tool in the study of chemistry, allowing for the prediction of an element's reactivity and the types of bonds it can form.