Potassium (K) will most likely form potassium bromide (KBr) when it combines with bromine (Br). This is because potassium typically loses one electron to achieve a stable electron configuration, forming a K⁺ ion, while bromine tends to gain an electron to form a Br⁻ ion. The result is the ionic compound KBr.
Magnesium (Mg), on the other hand, will most likely form magnesium bromide (MgBr₂) when it combines with bromine. Magnesium generally loses two electrons to achieve a stable electron configuration, resulting in a Mg²⁺ ion. Since each bromine atom gains one electron to become a Br⁻ ion, two bromine ions are needed to balance the charge of one magnesium ion. Thus, the resulting compound is MgBr₂.
In summary:
- Potassium (K) forms potassium bromide (KBr).
- Magnesium (Mg) forms magnesium bromide (MgBr₂).