Question

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

Short answer

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

Step-by-step solution

Understand the electron configuration notation

In the given electron configuration [Ar] 4s² 3d⁶, [Ar] refers to the electron configuration of the noble gas Argon. The remaining electron configuration, 4s² 3d⁶, indicates that there are 2 electrons in the 4s orbital and 6 electrons in the 3d orbital.

Determine the atomic number of Argon

In the periodic table, Argon has an atomic number of 18, which means it has 18 electrons. The electron configuration for Argon is [Ne] 3s² 3p⁶, where [Ne] represents the electron configuration of the noble gas Neon.

Add the number of electrons from each shell

Now, let's add the number of electrons in each shell Total electrons = Atomic number of Argon (18) + 4s² electrons (2) + 3d⁶ electrons (6) Total electrons = 18 + 2 + 6 = 26

Identify the element with 26 electrons

In the periodic table, an element with 26 electrons is Iron (Fe). Iron has an atomic number of 26 and has the electron configuration [Ar] 4s² 3d⁶. So, the element with the given ground-state electron configuration is Iron (Fe).

Key concepts

Ground-State

The ground-state electron configuration is the arrangement of electrons in an atom at its lowest energy level. In simpler terms, it's how electrons are distributed in various atomic orbitals when they are not excited. Each element has a unique ground-state configuration that provides essential information about its chemical properties.
For example, the notation \[\text{[Ar]} 4s^2 3d^6\] denotes the ground-state electron configuration of Iron (Fe). This tells us the electrons are arranged in specific orbitals, following the principle of filling lower energy levels before higher ones. This is known as the Aufbau principle, crucial for predicting the behavior of atoms in chemical reactions.

Periodic Table

The periodic table is an organized chart of chemical elements, arranged by increasing atomic number, electron configurations, and recurring chemical properties. This ingenious design helps chemists easily identify elements and understand their characteristics.

• Elements are divided into rows called periods and columns called groups or families.
• Each element's position in the table provides important clues, such as its atomic number, electronic configuration, and chemical behavior.
• The periodic table plays a vital role in determining the electron configuration of elements, as it shows the correct order of filling electronic orbitals using visual cues.

Understanding the periodic table is like having a map of atoms, guiding you through their mysterious behaviors and interactions.

Atomic Number

An element's atomic number represents the number of protons in its nucleus and, in a neutral atom, it also equals the number of electrons. It's a fundamental property that uniquely identifies each element.
For example, iron has an atomic number of 26. This means each iron atom contains 26 protons in the nucleus and, when neutral, 26 electrons orbiting around it. Knowing the atomic number helps us determine the electron configuration, which is essential for understanding chemical properties and behaviors.
The atomic number not only helps find an element on the periodic table but also ties directly to the element's identity and characteristics.

Iron (Fe)

Iron, represented by the symbol Fe, is an essential element in our periodic table due to its extensive usage and vital role in biology and industry. With an atomic number of 26, iron is a transition metal, which means it belongs to a group of elements known for their interesting electron configurations and diverse chemical behaviors.

• Iron has the electron configuration \[\text{[Ar]} 4s^2 3d^6\], indicating a filling of s and d orbitals particular to transition metals.
• It plays a crucial role in biology, as a component of hemoglobin in blood that helps transport oxygen.
• Iron is widely used in construction and manufacturing due to its strength and versatility.

Understanding iron's electron configuration reveals insights into its magnetic properties and reactivity, both key aspects of its applications in daily life.