Answer:
sp²
Explanation:
The trhichlorostannanide anion has molecular formula SnCl₃⁻, Sn is the central atom, which is at the group 14 of the periodic table, so it has 4 valence electrons. It must form 4 bonds to be stable.
In the anion, the tin (Sn) forms 3 bonds, so, it has 1 electron that is isolated. According to the VSEPR theory, the geometry of a molecule depends on the bonded electrons and the lone pairs, because the repulsive force between them will form the angles of the molecule.
Thus, only the bonded electrons will contribute, and because of that, the geometry will be trigonal planar.
To form the bonds, the subshells (s, p, d, f) of the atoms in the bond must interact. But, only isolated electrons can bond, so, to be stable and form the compounds, some atoms have hybrids shells, which are formed by the join of subshells.
The hybridization can be found by the determination of how many bonds are done, or by the geometry. For a trigonal planar geometry, the hybridization is sp², which means that the orbital is formed by one orbital s and two orbitals p.
