# Homework Help: How many other atoms is the central atom bonded to ?

1. Oct 10, 2009

### butterwings

1. The problem statement, all variables and given/known data

For the molecule ICl3

I) How many lone pairs of electrons are on the central atom?

II) How many other atoms is the central atom bonded to ?

III) What is the molecular geometry of the molecule?

IV) What is the electron-pair geometry?

a) triangular planar b) tetrahedral

c) triangular pyramidal d) octahedral

e) triangular bipyramidal f) linear

g) angular h) square planar

i) see-saw j) T shaped

k) square pyramid

2. Relevant equations

No formula needed.

3. The attempt at a solution
I want to know if I am correct: or anyone will agree that
I. 2
II. 5
III. e
IV. j

Thank you!

Last edited: Oct 10, 2009
2. Jan 19, 2017

### TeethWhitener

Ugh, ICl3 doesn't exist as a monomer (maybe in the gas phase). But let's play along...

7 valence electrons, 3 tied up in covalent bonds leaves 4 electrons (2 lone pairs).

Not sure how you got 5, since there's only 4 atoms in the whole compound. The correct answer is 3.

Again, triangular bipyramidal assumes 5 atoms around the central atom. In our case, we have 3 atoms and 2 electron pairs. So including the electron pairs, triangular bipyramidal is a good place to start. But since you only have 3 atoms, 2 of the equatorial spots are occupied by the electron pairs. This leaves the remaining 3 atoms in a T-shaped configuration, as predicted by VSEPR theory.

Again, according to VSEPR theory, the electron pairs will be oriented at an angle to one another.