1. What shape would you expect for \rm XeF4?

bond-angles

#1
  1. What shape would you expect for \rm XeF4?
  2. What are the expected bond angles in\rm ICl4+?

Check all that apply.
image

Concepts and reason
Valence Shell Electron Pair Repulsion (VSEPR) Theory:
In chemistry, VSEPR is a tool used to identify the geometry of the central atom which is surrounded by pairs of electrons (bonding and lone pairs). It is predicted only by repulsions between electron pairs present in the central atom.

Fundamentals
VSEPR Chart:
image

Descending order of repulsive interactions between electron pairs:

  • Lone pair – lone pair
  • lone pair – bond pair
  • bond pair – bond pair

Answer:

(1)
The central atom in a molecule is Xe.
The number of valence electrons in Xe is 8 electrons.
The number of lone pair electrons on Xe is 2 pairs.
The number of pairs of electrons around the central atom is 6 pairs.

For the given molecule, xenon is a central atom due to its low electronegativity. It has eight valence electrons in the outer electronic configuration. Four electrons are shared by four fluorine atoms, and the remaining electrons are non-bonding electrons which are four in total. Therefore, the number of pairs of electrons around the central atom is six pairs.

Number of lone pairs = 2
Number of bond pairs = 4
Total number of electron pairs = 6
So, the electron pair geometry is octahedral.
image
image

The electron pair geometry around the central atom is predicted by VSEPR theory. In a given molecule, one can calculate the number of electron pairs which is the sum of the number of bond pairs and the number of lone pairs. In this molecule, the total number of electron pairs is six which corresponds to the octahedral electron pair geometry. But, molecular geometry is square planar.

(2)
Number of valence electrons in iodine = 7 electrons
Net charge of image = +1 charge
Number of lone pairs = 1 pair
Number of bond pairs = 4 pairs
Number of pairs of electrons = 5 pairs
Therefore, the electron pair geometry is trigonal bipyramid based on VSEPR.

image
The electron pair geometry of imageis trigonal bipyramid which is predicted using the VSEPR theory and its bond angles are 90o, 120o and 180o.