Question

To which element does each of the following abbreviated electron configurations refer? a. \([\mathrm{Ne}] 3 s^{2} 3 p^{1}\) b. \([\mathrm{Ar}] 4 s^{1}\) c. \([\mathrm{Ar}] 4 s^{2} 3 d^{10} 4 p^{5}\) d. \([\mathrm{Kr}] 5 s^{2} 4 d^{10} 5 p^{2}\)

Short answer

a. Aluminum (Al) b. Potassium (K) c. Bromine (Br) d. Tin (Sn)

Step-by-step solution

Understand electron configurations

Electron configuration is the distribution of electrons in the orbitals of an atom. The abbreviated electron configurations use noble gas abbreviations in the square brackets []. This means that the electron configuration of the element in question starts with the electron configuration of the noble gas mentioned in the square brackets, followed by the remaining orbital notations.

Calculate the total number of electrons in each configuration

For each configuration, sum up the number of electrons by adding the superscripts. a. \([\mathrm{Ne}] 3s^{2} 3p^{1}\) --> Ne has 10 electrons, so the total number of electrons is \(10 + 2 + 1 = 13\) b. \([\mathrm{Ar}] 4s^{1}\) --> Ar has 18 electrons, so the total number of electrons is \(18 + 1 = 19\) c. \([\mathrm{Ar}] 4s^{2} 3d^{10} 4p^{5}\) --> Ar has 18 electrons, so the total number of electrons is \(18 + 2 + 10 + 5 = 35\) d. \([\mathrm{Kr}] 5s^{2} 4d^{10} 5p^{2}\) --> Kr has 36 electrons, so the total number of electrons is \(36 + 2 + 10 + 2 = 50\)

Identify the elements using the periodic table

Using the total number of electrons, which is equal to the atomic number, look for the corresponding elements in the periodic table. a. 13 electrons --> Element with atomic number 13 is Aluminum (Al) b. 19 electrons --> Element with atomic number 19 is Potassium (K) c. 35 electrons --> Element with atomic number 35 is Bromine (Br) d. 50 electrons --> Element with atomic number 50 is Tin (Sn)

Final answer

a. Aluminum (Al) b. Potassium (K) c. Bromine (Br) d. Tin (Sn)

Key concepts

Periodic Table

The periodic table is a remarkable tool in the world of chemistry. Arranged in order of increasing atomic numbers, it showcases elements based on their chemical properties. Each element occupies a position in a grid layout, where rows are called periods and columns are known as groups. One of its most fascinating features is how it can predict elemental behavior and electronic structure.

The layout helps understand electron configurations. As you move across a period from left to right, the atomic number increases, which means more electrons are added to the same energy level. Despite changes in energy levels, the group elements often share similar chemical properties due to having the same number of valence electrons. These similarities make the periodic table a powerful predictive tool.

• The table consists of metals, nonmetals, and metalloids, each with distinct properties.
• Noble gases, located in group 18, are particularly important for understanding electron configurations.
• The development of this table is attributed largely to Russian chemist Dmitri Mendeleev.

Understanding the periodic table's setup and what each element represents is essential for grasping more complex chemical concepts.

Atomic Number

The atomic number is a fundamental characteristic of an element, representing the number of protons in the nucleus of an atom. It serves as a unique identifier for each element on the periodic table. In a neutral atom, the atomic number also equals the number of electrons surrounding the nucleus. This number is crucial in determining an element's identity and positioning within the periodic table.

When dealing with electron configurations, the atomic number guides the arrangement of electrons across different energy levels, or shells. The lowest energy levels fill first, following the order dictated by the Aufbau principle.

• The atomic number not only distinguishes elements but also influences their properties and behavior.
• A change in the atomic number results in a completely different element.
• For example, increasing the atomic number from 13 (Aluminum) to 14 (Silicon) results in a change from a metal to a metalloid, highlighting the atomic number's impact.

This number is pivotal in systematically organizing the periodic table and understanding the basis of element classification.

Noble Gases

Noble gases are a group of elements in the 18th column (Group 18) of the periodic table, including helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements are renowned for their stability and lack of reactivity, due to having fully filled electron shells.

This unique stability makes noble gases ideal reference points in abbreviated electron configurations. For example, in the configuration \[ \text{[Ne]} 3s^2 3p^1 \], neon (Ne), a noble gas, indicates the configuration starts with neon's electron arrangement, simplifying understanding and representation of subsequent elements' configurations.

• Noble gases have a complete octet in their outer shell, except helium, which has a complete duplet.
• Their chemical inertness is due to their full valence shell, which reduces tendencies to gain or lose electrons.
• Neon and argon are commonly used in lighting and welding, while helium is utilized in balloons and as a coolant in various applications.

Recognizing the role of noble gases in electron configurations aids in the intuitive understanding of other elements' electronic structures.