Question

What noble gas has the same election 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 configuration as the ions in the given compounds are as follows: a. Cesium sulfide: Krypton (Kr) b. Strontium fluoride: Strontium ion (Sr²⁺) - Krypton (Kr), Fluorine ion (F⁻) - Helium (He) c. Calcium nitride: Calcium ion (Ca²⁺) - Argon (Ar), Nitrogen ion (N³⁻) - Helium (He) d. Aluminum bromide: Aluminum ion (Al³⁺) - Neon (Ne), Bromine ion (Br⁻) - Krypton (Kr)

Step-by-step solution

a. Cesium sulfide

Cesium (Cs) is an alkali metal in group 1 and forms a 1+ ion (Cs+). Sulfur (S) is a non-metal in group 16 and forms a 2- ion (S²⁻). When combined, these two ions form the compound cesium sulfide (Cs₂S). Cesium loses one electron when forming a Cs+ ion, and sulfur gains two electrons when forming an S²⁻ ion. Thus, both ions will have the same electron configuration: Cs+: [Kr] S²⁻: [Kr] The noble gas with the same electron configuration as both these ions is krypton (Kr).

b. Strontium fluoride

Strontium (Sr) is an alkaline earth metal in group 2 and forms a 2+ ion (Sr²⁺). Fluorine (F) is a halogen in group 17 and forms a 1- ion (F ⁻). The compound strontium fluoride (SrF₂) is formed by these two ions. Strontium loses two electrons when forming an Sr²⁺ ion, and fluorine gains one electron when forming an F⁻ ion. The electron configuration of both ions is as follows: Sr²⁺: [Kr] F⁻: [He] The noble gas with the same electron configuration as Sr²⁺ is krypton (Kr) and as F⁻ is helium (He).

c. Calcium nitride

Calcium (Ca) is an alkaline earth metal in group 2 and forms a 2+ ion (Ca²⁺). Nitrogen (N) is a non-metal in group 15 and forms a 3- ion (N³⁻). These ions make up the compound calcium nitride (Ca₃N₂). Calcium loses two electrons when forming an Ca²⁺ ion, and nitrogen gains three electrons when forming an N³⁻ ion. The electron configurations are as follows: Ca²⁺: [Ar] N³⁻: [He] The noble gas with the same electron configuration as Ca²⁺ is argon (Ar), and as N³⁻ is helium (He).

d. Aluminum bromide

Aluminum (Al) is a metal in group 13 and forms a 3+ ion (Al³⁺). Bromine (Br) is a halogen in group 17 and forms a 1- ion (Br⁻). The compound aluminum bromide (AlBr₃) consists of these ions. Aluminum loses three electrons when forming an Al³⁺ ion, and Bromine gains one electron when forming a Br⁻ ion. We can write the electron configurations as: Al³⁺: [Ne] Br⁻: [Kr] The noble gas with the same electron configuration as the Al³⁺ ion is neon (Ne), and as the Br⁻ ion is krypton (Kr).