To classify diatomic species as ionic, polar covalent, or non-polar covalent, we need to look at the differences in electronegativity between the atoms involved.
1. BrF (Bromine Monofluoride)
BrF is categorized as a polar covalent compound. The electronegativity of bromine (Br) is approximately 2.96, while that of fluorine (F) is about 3.98. The difference in electronegativity between fluorine and bromine is significant, which leads to an unequal sharing of electrons. As a result, the bond between Br and F is polar, with fluorine having a slight negative charge due to its higher electronegativity.
2. KF (Potassium Fluoride)
KF is classified as an ionic compound. In this case, potassium (K) has an electronegativity of approximately 0.82, and fluorine (F), as mentioned, is around 3.98. The electronegativity difference is very large, indicating a complete transfer of electrons from potassium to fluorine. This results in the formation of K+ and F– ions, creating strong electrostatic forces between them that characterize ionic bonds.