Question

Identify the following elements. a. An excited state of this element has the electron configuration \(1 s^{2} 2 s^{2} 2 p^{5} 3 s^{1}\). b. The ground-state electron configuration is \([\mathrm{Ne}] 3 s^{2} 3 p^{4}\). c. An excited state of this element has the electron configuration \([\mathrm{Kr}] 5 s^{2} 4 d^{6} 5 p^{2} 6 s^{1}\) d. The ground-state electron configuration contains three unpaired \(6 p\) electrons.

Short answer

a. The excited state element is Neon (Ne) with atomic number 10. b. The ground-state element is Sulfur (S) with atomic number 16. c. The excited state element is Silver (Ag) with atomic number 47. d. The ground-state element with three unpaired 6p electrons is Bismuth (Bi) with atomic number 83.

Step-by-step solution

Calculate the Atomic Number

Add the number of electrons in the excited state configuration: 2(1s^2) + 2(2s^2) + 5(2p^5) + 1(3s^1) = 10

Identify the Element

Using the periodic table, find the element with atomic number 10. The element is Neon (Ne). The given electron configuration is an excited state of Neon. #b. Identify the element with ground state electron configuration [Ne] 3s^2 3p^4#

Calculate the Atomic Number

[Ne] represents the electron configuration of Neon with 10 electrons. Add the number of electrons in the given configuration: 10(Ne) + 2(3s^2) + 4(3p^4) = 16

Identify the Element

Using the periodic table, find the element with atomic number 16. The element is Sulfur (S). The given electron configuration is the ground state of Sulfur. #c. Identify the element with excited state electron configuration [Kr] 5s^2 4d^6 5p^2 6s^1#

Calculate the Atomic Number

[Kr] represents the electron configuration of Krypton with 36 electrons. Add the number of electrons in the given configuration: 36(Kr) + 2(5s^2) + 6(4d^6) + 2(5p^2) + 1(6s^1) = 47

Identify the Element

Using the periodic table, find the element with atomic number 47. The element is Silver (Ag). The given electron configuration is an excited state of Silver. #d. Identify the element with ground state electron configuration containing three unpaired 6p electrons#

Find the electron configuration with unpaired 6p electrons

An element with three unpaired 6p electrons will have electron configuration ending in 6p^3.

Calculate the Atomic Number

Find an element with electron configuration ending in 6p^3: [Xe] 6s^2 4f^14 5d^10 6p^3, where [Xe] represents the electron configuration of Xenon with 54 electrons. Add the number of electrons in the given configuration: 54(Xe) + 2(6s^2) + 14(4f^14) + 10(5d^10) + 3(6p^3) = 83

Identify the Element

Using the periodic table, find the element with atomic number 83. The element is Bismuth (Bi). The given electron configuration is the ground state of Bismuth containing three unpaired 6p electrons.

Key concepts

Atomic Number

The atomic number is a fundamental characteristic of an element. It refers to the number of protons present in the nucleus of an atom and is denoted by the symbol 'Z'. Since atoms are electrically neutral, the atomic number also equals the number of electrons in a neutral atom. It serves as an identifier for the elements and determines their position on the periodic table.

For instance, when solving problems related to electron configurations, the total count of electrons gives us the atomic number of the element. It's not just a count; the atomic number connects deeply with the chemical properties of the element, such as reactivity and bonding behavior. As the atomic number increases, elements exhibit a greater variety of available electron configurations, leading to a diversity of chemical characteristics.

Excited State

When it comes to electron configurations, the excited state refers to an arrangement of an atom’s electrons that is higher in energy than the ground state. In the ground state, electrons fill the lowest available energy orbitals. However, when energy is absorbed, electrons can 'jump' to higher energy levels. This state is temporary; as electrons return to lower energy levels, they release energy, often as visible light or other forms of electromagnetic radiation.

In exercises, identifying an excited state often involves recognizing that electrons are not in their typical lowest-energy positions. For example, an unusual configuration like one where a normally empty outer orbital has an electron suggests that the atom is in an excited state. This can help to determine which element is being described when matched with the atomic number.

Ground State

The ground state is the lowest energy state of an atom, where all electrons are in the lowest possible energy levels according to the Pauli exclusion principle and Hund’s rule. This is the most stable and common state for atoms. The ground state electron configuration is what we often see in periodic tables and use as a reference for determining an element's typical chemical behavior.

It is essential to understand an element’s ground state electron configuration to predict how it will likely interact or bond with other atoms. When we say an atom is in its ground state, we’re effectively describing its ‘normal’ condition, absent any added energy that might cause electrons to occupy higher-energy orbitals.

Periodic Table

The periodic table is more than just a chart of the elements; it's a profound tool that reflects the underlying principles of quantum mechanics and the organization of the electron shells in atoms. Elements are arranged by increasing atomic number and by changes in chemical and physical properties. For many exercises dealing with electron configurations, the periodic table serves as the map for navigating through the elements.

Understanding how to read and interpret the periodic table is crucial. It allows us to easily move from an electron configuration to identifying the element by observing the periodic trends. The table is divided into blocks corresponding to the outer electron orbital - s, p, d, and f - which helps in visualizing how electron configurations change across the table. By becoming familiar with the layout and the information the table encapsulates, students can swiftly apply this knowledge to determine the properties and behaviors of different elements.