Is BrO4^- polar or non -polar?

To determine whether BrO4^- (a polyatomic ion called bromate) is polar or non-polar, we need to determine its molecular geometry and its polarity.

1. Molecular Geometry: BrO4^- consists of a central bromine atom (Br) bonded to four oxygen atoms (O) and one additional oxygen atom with a negative charge (O^-). The arrangement is a tetrahedral shape, with the negative charge on one of the oxygen atoms.

2. Polarity: To determine polarity, we need to consider the electronegativity difference between the atoms. Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond. The greater the electronegativity difference between atoms, the more polar the bond.

In the case of BrO4^-, the bromine atom is less electronegative than the oxygen atoms. This means the oxygen atoms will pull the shared electrons closer to themselves, creating a partial negative charge (δ-) on the oxygen atoms and a partial positive charge (δ+) on the bromine atom.

However, the overall molecule is not symmetrical due to the presence of the negative charge on one of the oxygen atoms. This asymmetry leads to a net dipole across the molecule, making it polar.

Therefore, BrO4^- is a polar molecule.