Potassium and bromine combine to make KBr. What is the name of this compound?
The Correct Answer and Explanation is:
The compound formed by potassium (K) and bromine (Br) is potassium bromide (KBr).
Explanation:
When potassium (K), a metal, reacts with bromine (Br), a halogen, they form an ionic compound. The process is driven by the need to achieve a stable electron configuration for both atoms. Potassium, which is an alkali metal, has one electron in its outermost shell. Bromine, a halogen, has seven electrons in its outermost shell and requires one more electron to complete its octet and achieve a stable electron configuration.
Here’s how the reaction works:
- Electron Transfer: Potassium donates its one valence electron to bromine. This results in the formation of a potassium ion (K⁺) with a +1 charge (since it loses an electron) and a bromide ion (Br⁻) with a -1 charge (since it gains the electron).
- Ionic Bond Formation: The positively charged potassium ion (K⁺) and the negatively charged bromide ion (Br⁻) are attracted to each other due to electrostatic forces, forming an ionic bond. The compound KBr is held together by this ionic bond.
- Naming the Compound: In ionic compounds, the metal (cation) is named first, followed by the non-metal (anion). In this case, potassium is the cation, and bromine is the anion. Since the halogen bromine forms a bromide ion (Br⁻), the compound is called potassium bromide.
- Properties of KBr: Potassium bromide is a white, crystalline solid at room temperature. It is highly soluble in water and commonly used in applications such as in photography (as a silver bromide) and in medicine (as an anticonvulsant).
In summary, potassium bromide (KBr) is the ionic compound formed by the reaction of potassium and bromine. It follows typical rules of ionic bonding, where potassium donates an electron to bromine, forming a stable compound.