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### Bond Angles

Posted: Sun Nov 11, 2018 10:59 pm
Atoms in molecules have molecular shapes that try to get each atom as far away from each other. However, why are tetrahedral angles 109.5 degrees each instead of 90 degrees if we follow the rationale of 360degrees/4?

### Re: Bond Angles

Posted: Sun Nov 11, 2018 11:08 pm
We represent molecules using 2D Lewis structures, but they really exist in 3D space. This means that the atoms can get father away from each other, going behind or coming in front of the central atom, which explains the larger bond angle of 109.5

### Re: Bond Angles

Posted: Sun Nov 11, 2018 11:10 pm
In that instance you would have to consider a 3D model instead of a 2D model. The surrounding atoms want to be as far away from each other as possible so a three dimensional model provides the most space between the atoms.

### Re: Bond Angles

Posted: Sun Nov 11, 2018 11:15 pm
Tetrahedrals are 3D shapes, not 2D. If they were 2D shapes then the angles would be 90 degrees. Remember that the shapes of molecules should be in 3D since we live in a 3D world

### Re: Bond Angles

Posted: Sun Nov 11, 2018 11:16 pm
Tetrahedral shaped atoms have bonds at a 109.5 degree angle because of its 3 dimensional shape! If each bond was 90 degrees away from each other, it would be more similar to having a flat shape but to maximize the space that the atom has (and because of the negatively charged electron's repulsion from each other), the bonds are at a 109.5 degree angle.