KBr is an ionic compound. Identify which element is the cation and which element is the anion. Following the naming conventions you identified for ionic compounds, what would be the name for KBr?
The Correct Answer and Explanation is:
In the ionic compound potassium bromide (KBr), K (potassium) is the cation, and Br (bromine) is the anion.
Explanation:
- Identification of the cation and anion:
- Cation: The cation is the positively charged ion. In KBr, potassium (K) is in Group 1 of the periodic table, which means it has one electron in its outermost shell. When potassium forms an ion, it loses this electron to achieve a stable, full electron shell. This gives potassium a positive charge, resulting in the ion ( \text{K}^+ ).
- Anion: The anion is the negatively charged ion. Bromine (Br) is a halogen in Group 17, which means it has seven electrons in its outermost shell and needs one more electron to complete its octet. Bromine gains one electron to achieve a stable electron configuration, which gives it a negative charge, resulting in the ion ( \text{Br}^- ).
- Naming conventions for ionic compounds:
- Naming the cation: The name of the cation is simply the name of the element. In this case, the cation is potassium, so it remains as “potassium.”
- Naming the anion: The anion is named by taking the root of the element’s name and adding the suffix “-ide”. Since the anion is bromine, it becomes “bromide.”
- Name of the compound:
Combining the names of the cation and the anion, the ionic compound KBr is named potassium bromide.
Summary:
- Potassium (K) forms a cation (( \text{K}^+ )), and Bromine (Br) forms an anion (( \text{Br}^- )).
- Following the naming conventions for ionic compounds, the name of KBr is potassium bromide.