H20 Bent Structure

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Angel Gutierrez 2E
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H20 Bent Structure

Postby Angel Gutierrez 2E » Fri Nov 20, 2020 2:10 pm

Why is the H20 molecule bent? Why are the lone pairs in Oxygen next to each other when there should be a repulsion in lone pairs?

Chem_Mod
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Re: H20 Bent Structure

Postby Chem_Mod » Fri Nov 20, 2020 2:31 pm

Note that the parent electronic structure (considering both lone pairs and bonding pairs) of water is tetrahedral because there are 4 regions of electron density around the central oxygen - 2 lone pairs and 2 bonding pairs. For a tetrahedral geometry, each corner is equidistant from the other corners; in other words, there is not preferential location of bonding pairs or lone pairs like there is with a trigonal bipyramidal or octohedral geometry. When considering the molecular structure, we only consider the atoms, hence the shape of water is bent or angular (remove 2 corners ie. lone pairs from the tetrahedron). The lone pairs do increase the amount of electron pair repulsion however, which decreases the HOH bond angle to 104.5 degrees from the 109.5 degree angles of a normal tetrahedral geometry.

Olivia Smith 2E
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Re: H20 Bent Structure

Postby Olivia Smith 2E » Fri Nov 20, 2020 2:32 pm

It's because oxygen has 2 lone pairs that take up space. CO2 on the other hand does not have any lone pairs that is why it is straight across. I would visualize the lone pairs as almost like another bond, so each bond needs to be placed around the oxygen molecule like a box. For example in SF4 the S is surrounded by the Fs in a box like shape. The same goes for water, but because we usually do not denote the electrons it looks like an L as opposed to a box

Josh Chou 3K
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Re: H20 Bent Structure

Postby Josh Chou 3K » Fri Nov 20, 2020 2:33 pm

The H2O molecule is bent because there are 4 regions of electron density but only 2 bonding pairs. Dr. Lavelle demonstrated this in class with a foam model by starting with the tetrahedron-shaped molecule and then removing 2 of the atoms. Hope this helps!

Maya Johnson 2a
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Re: H20 Bent Structure

Postby Maya Johnson 2a » Fri Nov 20, 2020 2:46 pm

H2O has a bent structure because it has two lone pairs on the oxygen atom. This causes repulsion of the two hydrogen atoms and pushes them downwards, causing a bent structure.

Madison Muggeo 3H
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Re: H20 Bent Structure

Postby Madison Muggeo 3H » Fri Nov 20, 2020 7:34 pm

Hi! The lone pairs on the oxygen repel each other and take up space, "bending" the hydrogen atoms downward. Hope this helps!

Eric Cruz 2G
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Re: H20 Bent Structure

Postby Eric Cruz 2G » Fri Nov 20, 2020 11:56 pm

The reason H2O is bent is due to the high amount of repulsions that is caused by the two lone pairs. As Lavelle emphasized in his lecture, the most powerful repulsion occurs between two lone pairs. Therefore, since oxygen has two lone pairs on its central atom and two bond pairs, the two bonds are repelled by the high electron density of the two lone pairs. Consequently, rather than being linear, its bond angles are positioned downwards at a 104 degree angle.

jessicasilverstein1F
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Re: H20 Bent Structure

Postby jessicasilverstein1F » Sat Nov 21, 2020 11:37 am

The reason that H20 is bent is because the oxygen has two lone pairs. These lone pairs cause repulsion of the two hydrogen atoms and pushes them downwards, thus causing a bent structure in the molecule

Nhu Pham-Dis3G
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Re: H20 Bent Structure

Postby Nhu Pham-Dis3G » Sat Nov 21, 2020 4:28 pm

The H20 molecule is bent because there are two lone pairs and they are located on the same side. Because of their proximity to each other, there is repulsion, which results in the bent shape.

Jerry_T
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Re: H20 Bent Structure

Postby Jerry_T » Sat Nov 21, 2020 11:26 pm

The lone pairs are more repulsive than the bonding pairs and thus their electron distribution causes H2O to be bent as the lone pairs "push down" on the H atoms.

Chudi Onyedika 3A
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Re: H20 Bent Structure

Postby Chudi Onyedika 3A » Sun Nov 22, 2020 9:35 pm

The space taken by the two lone pairs results in the hydrogen atoms being pushed downwards.

Colin Squire 3B
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Re: H20 Bent Structure

Postby Colin Squire 3B » Sun Nov 22, 2020 9:42 pm

Due to the three domains of electron density, two of which being bonded pairs, and the other being a lone pair, the overall shape of H20 is bent. This is partly due to the fact that the lone pair pushes the two bonded pairs down, if that makes any sense. Hope this helped :)

Ashley Lopez 3J
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Re: H20 Bent Structure

Postby Ashley Lopez 3J » Sun Nov 22, 2020 10:07 pm

H20 is bent because the two lone electron pairs that are on one side of the molecule cause a repulsion on the hydrogen atoms attached to the oxygen molecule. The repulsion is ultimately what induces the tetrahedral shape. I visualize it as each lone pair having the energy to push down (or up) on the H atoms.

Sydney Jensen 3L
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Re: H20 Bent Structure

Postby Sydney Jensen 3L » Mon Nov 23, 2020 1:53 pm

The two lone electron pairs want to stay as far apart as possible, and they repulse, causing the shape to be bent and the lone pairs to be as far away as possible.

Inderpal Singh 2L
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Re: H20 Bent Structure

Postby Inderpal Singh 2L » Mon Nov 23, 2020 2:04 pm

The two lone pairs repel each other, making them move away!


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