Question #9c01a

1 Answer
Apr 28, 2017

No two will have used the same number of d-orbitals. However, ICl_2^+ICl+2 and ICl_4^-ICl4 will each have two non-bonded electron pairs.

Explanation:

To apply the Valence Bond Theory, determine 1. the number of bonded pairs and 2. number of non-bonded pairs. Sum of BPrs + NBPrs => Number of Hybrids needed from valence structure. (Remember, Valence structure will be the highest principle quantum number of the electron configuration.)

Bonded Pairs (BPrs) = Number of elements attached to central element (we'll call these 'substrates'). Simply look at subscript after substrate element => number of bonded pairs.

Non-Bonded Pairs (NBPrs) = (Valence Number - Substrate Number) / 2
=> Valence Number is total number of valence electrons. If structure is cation, also subtract 1 e^-e to account for + charge or, if anion, add 1 e^-e to account for - charge.

=> Substrate Number is total electrons in valence of substrates when bonded. This will be '8' for all non-metals except hydrogen which will be '2'.

Number of Hybrids needed (all single bonds) = BPrs + NBPrs

ICl_2^+ICl+2 => 2 Bonded Pr & 2 Non-Bonded Pr => 4 e^-epair => 4 hybrids needed.

I[Kr]4d^104d105s^25s25p_x^25p2xp_y^2p2y5p_z^15p1z => I[Kr](#4d^105s^2#5p_x^25p2xp_y^1p1y5p_z^1)^+5p1z)+ + e^-e
=> I[Kr][4d^104d105(sp_3)^25(sp3)2(sp_3)^2(sp3)2(sp_3)^1(sp3)1(sp_3)^1]^+(sp3)1]+

4 (sp_3)(sp3) Hybrid Orbitals => AX_4AX4 Geometry => Tetrahedron with 2 bonded pair of electrons (Chloride substrates) and 2 non-bonded pair of electrons. (No d-orbitals used)

Apply same sequence to remaining formulas of interest.
ICl_2^-ICl2 => 2 Bonded Pr; 3 NBPr => Trigonal Bipyrimid Parent (AX_5)(AX5) => (AX_2E_3)(AX2E3) Geometry (Linear). (1 d-orbital used)

IF_7IF7 => 7 BPrs; 0 NBPr => AX_7AX7 Parent (Pentagonal Bipyrimid) which is also the structural geometry. (3 d-orbitals used)

ICl_4^-ICl4 => 4 BPrs; 2 NBPrs => AX_6AX6 Parent (Octahedron) => AX_4E_2AX4E2 Geometry (Square Planar). (2 d-orbitals used)