Question

What noble gas has the same electron configuration as each of the ions in the following compounds? a. cesium sulfide b. strontium fluoride c. calcium nitride d. aluminum bromide

Short answer

The noble gases with the same electron configurations as the ions in the given compounds are: a. Cesium sulfide - Argon (Ar) b. Strontium fluoride - Neon (Ne) c. Calcium nitride - Neon (Ne) d. Aluminum bromide - Krypton (Kr)

Step-by-step solution

a. Cesium sulfide

First, we need to find the electron configuration of the cesium ion (Cs+) and the sulfide ion (S²⁻). 1. Cesium (Cs) has an atomic number of 55, so its electron configuration is [Xe] 6s¹. When it loses one electron to form the cesium ion (Cs+), the electron configuration will be [Xe]. 2. Sulfur (S) has an atomic number of 16, so its electron configuration is [Ne] 3s² 3p⁴. When it gains two electrons to form the sulfide ion (S²⁻), the electron configuration becomes [Ne] 3s² 3p⁶, which is the same as that of the noble gas Argon (Ar). So, the noble gas that has the same electron configuration as the ions in cesium sulfide is Argon (Ar).

b. Strontium fluoride

Now, let's find the electron configuration of the strontium ion (Sr²⁺) and the fluoride ion (F⁻). 1. Strontium (Sr) has an atomic number of 38, so its electron configuration is [Kr] 5s². When it loses two electrons to form the strontium ion (Sr²⁺), the electron configuration will be [Kr]. 2. Fluorine (F) has an atomic number of 9, so its electron configuration is [He] 2s² 2p⁵. When it gains one electron to form the fluoride ion (F⁻), the electron configuration becomes [He] 2s² 2p⁶, which is the same as that of the noble gas Neon (Ne). So, the noble gas that has the same electron configuration as the ions in strontium fluoride is Neon (Ne).

c. Calcium nitride

Next, let's find the electron configuration of the calcium ion (Ca²⁺) and the nitride ion (N³⁻). 1. Calcium (Ca) has an atomic number of 20, so its electron configuration is [Ar] 4s². When it loses two electrons to form the calcium ion (Ca²⁺), the electron configuration will be [Ar]. 2. Nitrogen (N) has an atomic number of 7, so its electron configuration is [He] 2s² 2p³. When it gains three electrons to form the nitride ion (N³⁻), the electron configuration becomes [He] 2s² 2p⁶, which is the same as that of the noble gas Neon (Ne). So, the noble gas that has the same electron configuration as the ions in calcium nitride is Neon (Ne).

d. Aluminum bromide

Finally, let's find the electron configuration of the aluminum ion (Al³⁺) and the bromide ion (Br⁻). 1. Aluminum (Al) has an atomic number of 13, so its electron configuration is [Ne] 3s² 3p¹. When it loses three electrons to form the aluminum ion (Al³⁺), the electron configuration will be [Ne]. 2. Bromine (Br) has an atomic number of 35, so its electron configuration is [Ar] 4s² 3d¹⁰ 4p⁵. When it gains one electron to form the bromide ion (Br⁻), the electron configuration becomes [Ar] 4s² 3d¹⁰ 4p⁶, which is the same as that of the noble gas Krypton (Kr). So, the noble gas that has the same electron configuration as the ions in aluminum bromide is Krypton (Kr).

Key concepts

Noble Gases

Noble gases are a unique group of elements in the Periodic Table that are known for their stability. They include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements are stable due to their electron configuration, which is typically a full valence shell. This gives them little tendency to react with other elements to form compounds. The electron configuration of noble gases makes them a reference point when comparing other elements and ions.

Many ions achieve stability by attaining an electron configuration similar to that of a nearby noble gas. For example, the cesium ion (Cs⁺) and the sulfide ion (S²⁻) in cesium sulfide (Cs₂S) match the electron configuration of xenon (Xe) and argon (Ar) respectively. This is because cesium loses one electron to stabilize as Cs⁺ resembling [Xe], and sulfur gains two electrons to become S²⁻ resembling [Ar].

• Stability from full valence shell
• Reference point for ion electron configuration
• Important in chemical reactions to find inert nature

Ions

Ions are charged particles formed when atoms lose or gain electrons to attain a stable electron configuration similar to that of noble gases. There are two types of ions: cations and anions. Cations are positively charged ions, formed when an atom loses electrons, while anions are negatively charged ions, formed when an atom gains electrons.

For instance, strontium (Sr) forms a cation by losing two electrons to become Sr²⁺ with an electron configuration similar to krypton (Kr), specifically denoted as [Kr]. Meanwhile, fluoride ions in strontium fluoride become F⁻ by gaining one electron to achieve the stable configuration of neon (Ne).

• Cations: Positively charged by losing electrons
• Anions: Negatively charged by gaining electrons
• Achieve configurations of nearest noble gases

Chemical Compounds

Chemical compounds are substances made of two or more different elements chemically bonded together. They can be ionic or molecular in nature. Ionic compounds, such as calcium nitride (Ca₃N₂), form when metals transfer electrons to nonmetals, resulting in a composition of ions.

In calcium nitride, calcium (Ca) loses two electrons per atom to form a Ca²⁺ ion, achieving the electron configuration of argon (Ar). Nitrogen (N) gains three electrons to become N³⁻, matching the electron configuration of neon (Ne). The interplay between ions leads to the formation of stable compounds.

• Ionic: Involves transfer of electrons
• Molecular: Sharing of electrons between elements
• Stability through ion partnerships

Periodic Table

The Periodic Table is a comprehensive arrangement of all known elements, organized according to increasing atomic number, typically in rows called periods. It helps to visualize recurring trends or periodicity in properties such as reactivity, electronegativity, and atomic size.

Elements are arranged in groups or families that share similar properties due to having the same number of electrons in their outer shells. This is essential for determining the reactivity and potential bonding of an element, as demonstrated with elements forming ions to mimic noble gas electron configurations. For example, aluminum (Al) in aluminum bromide forms Al³⁺ with [Ne] configuration, while bromine becomes Br⁻ resembling [Kr] configuration.

• Organized by atomic number
• Groups share properties
• Guides understanding of element reactivity