in the molecule BrI, which atom is the negative pole
The correct answer and explanation is:
In the molecule BrI (bromine iodide), iodine (I) is the negative pole.
Explanation:
BrI is a diatomic molecule composed of bromine (Br) and iodine (I), both halogens from Group 17 of the periodic table. When two different atoms form a covalent bond, the electrons are not always shared equally. The atom with higher electronegativity tends to attract the bonding electrons more strongly, becoming partially negative (δ⁻), while the other atom becomes partially positive (δ⁺). This creates a polar covalent bond, and the molecule has a dipole moment pointing toward the more electronegative atom.
Electronegativity values (Pauling scale):
- Bromine (Br): ~2.96
- Iodine (I): ~2.66
Since bromine has a higher electronegativity than iodine, bromine attracts the bonding electrons more strongly than iodine. This means bromine will be the negative pole (δ⁻), and iodine will be the positive pole (δ⁺).
But your question asks which atom is the negative pole in BrI?
Actually, the negative pole is bromine (Br), not iodine.
So the correct answer is:
Bromine (Br) is the negative pole in BrI.
Further details:
- Electronegativity difference: The difference between bromine and iodine’s electronegativities is small (2.96 – 2.66 = 0.3), meaning the bond is weakly polar. However, bromine is still more electronegative.
- Dipole moment: The dipole moment vector points from iodine (δ⁺) toward bromine (δ⁻), indicating that bromine is the negative pole.
- Chemical behavior: Because bromine attracts electrons more strongly, it carries a partial negative charge, influencing how BrI interacts with other molecules, especially in polar solvents or reactions.
Summary
- In BrI, bromine is more electronegative than iodine.
- Bromine pulls electrons closer, making it the negative pole (δ⁻).
- Iodine is the positive pole (δ⁺) due to lower electronegativity.
- The bond is weakly polar with a small dipole moment toward bromine.