Chemistry, 12.02.2020 04:39 winterblanco

1. Use VSEPR theory to decide which one of the following ions and molecules is likely to be planar. (The central atom is always first in the formula.) A. BrF3 B. H3O C. PCl3 D. SO42- E. SF4

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Answer from: hopeschr2019

Answer : The molecule likely to be planar is, BF_3

Explanation :

Formula used :

$\text{Number of electron pair}=\frac{1}{2}[V+N-C+A]$

where,

V = number of valence electrons present in central atom

N = number of monovalent atoms bonded to central atom

C = charge of cation

A = charge of anion

Now we have to determine the hybridization of the following molecules.

(A) The given molecule is, BF_3

$\text{Number of electrons}=\frac{1}{2}\times [3+3]=3$

The number of electron pair are 5 that means the hybridization will be sp^2 and the electronic geometry of the molecule will be trigonal planar.

(B) The given molecule is, H_3O^+

$\text{Number of electrons}=\frac{1}{2}\times [6+3-1]=4$

The number of electron pair are 4 that means the hybridization will be sp^3 and the electronic geometry of the molecule will be tetrahedral.

But as there are 3 atoms around the central oxygen atom, the fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be pyramidal.

$\text{Number of electrons}=\frac{1}{2}\times [5+3]=4$

The number of electron pair are 4 that means the hybridization will be sp^3 and the electronic geometry of the molecule will be tetrahedral.

But as there are 2 atoms around the central oxygen atom, the fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be pyramidal.

(d) The given molecule is, $SO_4^{2-}$

$\text{Number of electrons}=\frac{1}{2}\times [6+2]=4$

The number of electron pair are 4 that means the hybridization will be sp^3 and the electronic geometry of the molecule will be tetrahedral.

(E) The given molecule is, SF_4

$\text{Number of electrons}=\frac{1}{2}\times [6+4]=5$

The number of electron pair are 5 that means the hybridization will be sp^3d and the electronic geometry of the molecule will be tetrahedral.

But as there are 4 atoms around the central oxygen atom, the fifth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be sea-saw.

Hence, the molecule likely to be planar is, BF_3

Answer from: Quest

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

Answer from: Quest

Idk the answer sorry