VSEPR repulsion model
Moderators: Chem_Mod, Chem_Admin
-
- Posts: 54
- Joined: Sat Jul 20, 2019 12:15 am
Re: VSEPR repulsion model
VSEPR models takes in repulsion while determining the shape of the molecules and the subsequent angles that the bonds have. In general, repulsion strength follows the rule of:
lone-lone pair>lone-bonding pair>Bonding-Bonding pair
lone-lone pair>lone-bonding pair>Bonding-Bonding pair
-
- Posts: 102
- Joined: Thu Jul 25, 2019 12:17 am
Re: VSEPR repulsion model
As said above, the strength of repulsion would affect the angles, which will also affect the shape. a lone pair lone pair would have greater repulsion and so the bond angle would be larger because they can't get as close to each other
-
- Posts: 101
- Joined: Wed Feb 27, 2019 12:17 am
Re: VSEPR repulsion model
If there is repulsion between lone pairs, it would change the structure of the atom. We need to figure out how the lone pairs need to be arranged in each structure to minimise repulsion and find most stability.
-
- Posts: 97
- Joined: Fri Aug 02, 2019 12:16 am
Re: VSEPR repulsion model
In a VESPR model, there is repulsion between lone pairs and bonding pairs. In terms of strength, LP--LP Bonds > LP--Bonding > Bonding--Bonding. Because atoms want to be spread out in VESPR models, the lone pairs cause an increased amount of repulsion.
-
- Posts: 97
- Joined: Fri Aug 02, 2019 12:16 am
Re: VSEPR repulsion model
Bond angles also cannot be calculated, per say, using VESPR, but it can help you determine in in terms of steric numbers. For example, we know that methane (CH4) is a tetrahedral, and all bond angles are 109.5, but ammonia (NH3) which has the same principle shape as methane, except now has a lone pair instead of a 4th bonded atom created the shape trigonal pyramidal. The repulsion of the lone pair causes the angles to become smaller, so the angles for a trigonal pyramidal are about 107, but more importantly it is <109.5.
Re: VSEPR repulsion model
How do you make sure your'e using the correct Lewis structure when estimating the bond angle?
-
- Posts: 76
- Joined: Wed Sep 18, 2019 12:16 am
Re: VSEPR repulsion model
Repulsion helps to determine shape and bond angle. The stronger bonds must be further apart.
Re: VSEPR repulsion model
Repulsion plays a large role. It determine both the general arrangement of the atoms in molecules and the specific angles between bonds. Repulsion makes it important that electron clouds are located as far from each other as possible.
Return to “Determining Molecular Shape (VSEPR)”
Who is online
Users browsing this forum: No registered users and 6 guests