Predict the electron pair geometry, the molecular shape, and the bond angle for a dichlorine mon

Predict the electron pair geometry, the molecular shape, and...

Key Concepts

Molecular Geometry

Molecular geometry describes the arrangement of only the atoms in a molecule, excluding the lone pairs. When the central atom has lone pairs, they occupy positions in the electron geometry that influence the overall shape of the molecule. For example, a central atom with two bonding pairs and two lone pairs adopts a bent shape.

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) theory is a model used to predict the three-dimensional shape of molecules based on the repulsion between electron pairs in the valence shell of the central atom. The theory proposes that electron pairs arrange themselves as far apart as possible to minimize repulsion, which in turn determines both the electron geometry and the molecular shape.

Electron Pair Geometry

Electron pair geometry refers to the spatial arrangement of all electron pairs (both bonding pairs and lone pairs) around the central atom. For a central atom with a steric number of four (meaning it is surrounded by four regions of electron density), the ideal electron pair geometry is tetrahedral.

Lone Pair Repulsion

Lone pairs exert a stronger repulsive force than bonding pairs because they are localized closer to the central atom. This increased repulsion causes the bonding pairs to be pushed slightly closer together, which reduces the bond angle from the idealized angle predicted by the electron pair geometry.

Bond Angle Predictions

Bond angles are determined by the resultant spatial arrangement from VSEPR considerations. In a tetrahedral electron pair geometry, the ideal bond angle is 109.5°. However, the presence of lone pairs (as in a bent molecular geometry with two lone pairs and two bonding pairs) reduces the bond angle, often to a value near 104–107°, depending on the specific molecule.

Transcript

00:01 We're going to be talking about vesper, which is the valens shell electron repulsion theory and how we can use it in order to allow us to determine the electron pair geometry as well as the molecular shape of our molecule and help us predict the bond angles that we have.

00:17 So again, what is vesper? as i mentioned or just a second ago, it's a valence cell electron repulsion theory.

00:24 And what this allows us to do is to predict the geometry of individual molecules based from the number of loan pairs and the number of bonds that a particular central atom has.

00:35 So an example that i have here is cl2o, which is dichlorine monoxide.

00:43 So we'll go ahead and start drawing the lewis structure for dichlorine monoxide.

00:48 And then using the vesper theory, we'll also are drawing a little bit to help.

00:54 Us really determine how the molecule actually looks like a little bit more accurately.

01:00 So let's go ahead and start drawing it.

01:03 We'll start with oxygen as our essential atom because it can make more bonds than chlorine.

01:08 Remember chlorine is a halogen.

01:11 It's on the column number seven of the periodic table and it's able to make one bond only because it has one more electron.

01:18 It needs one more electron in order to fulfill its octet.

01:22 Whereas oxygen needs two more because it has six valence electrons and you need eight electrons to fulfill lactate, right? so it's going to need two more electrons, so it's going to make two bonds.

01:33 So that's why we're going to start with oxygen as our central atom.

01:38 And let's just go ahead and start putting our six valence electrons that oxygen has.

01:47 So now let's go ahead and start putting the chlorines around it.

01:57 And let's make sure we feel it's octets and whatnot.

02:03 And let's go ahead and add another little pair.

02:05 Remember, because each chlorine donated one electron, so those are going to be the electrons that we have here at the bottom of oxygen.

02:12 So this is pretty much what it's going to look like in terms.

02:15 It's a very simplistic structure of dichlorine monoxide, but we're going to alter it in just a second using our vesper theory.

02:23 So i have a chart here on the left.

02:25 It kind of shows us here on the first column.

02:28 Here we have 2, 3, 4, 5, 6.

02:30 That's pretty much it just only tells you how many things are surrounding the central atom.

02:36 And then we'll go ahead and start altering the shape of the molecule here based on the number of lone pairs and bonds it has.

02:42 So let's see.

02:45 Dichlorine monoxide has two things around it, right? oxygen is the central atom and there's two things around it.

02:51 So we're going to start here...

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