Answer:
The geometry of BF₄⁻ anion is <u>tetrahedral</u>
Explanation:
According to the Valence Bond Theory, the boron atom in BF₃ molecule is <em>sp² hybridized</em>. As one 2s and two 2p orbitals hybridize to form <em>three sp² hybrid orbitals. </em>
<u>Therefore, the molecular geometry of BF₃ molecule is </u><u><em>trigonal planar</em></u><u>.</u>
However, in a BF₄⁻ ion, the boron atom is <em>sp³ hybridized</em>. As it forms <em>four sp³ hybrid orbitals</em> by hybridization of one 2s and three 2p orbitals.
<u>Therefore, the molecular geometry of BF₄⁻ anion is </u><u><em>tetrahedral</em></u><u>.</u>