How are angles in molecules calculated?

[IDK10]

I understand how angles are calculated in compounds where an atom is bonded to 2, 3, 5, and 6 bonds (bond pair + lone pair). But how do they work out the angle of a compound where an atom has 4 bonds (i.e. methane), in this case the carbon atom, has a H-C-H angle of 109.5°

 

[Borek]

Please elaborate, I fail to see how it is different.

 

[IDK10]

Please elaborate, I fail to see how it is different.

In methane and any other compound containing an atoms which only has 4 bond pairs and 0 lone pairs of electrons. The bond between the three atoms (in the case of methane, it is the H-C-H bond angle), it is 109.5°, I was wondering how they worked that out.

 

[Borek]

And how they worked out the value for water molecule, or for any other molecule with any number of bonds and/or lone pairs?

I don't see why you say you know how to deal with other molecules, but you think this particular molecule is different.

 

[IDK10]

And how they worked out the value for water molecule, or for any other molecule with any number of bonds and/or lone pairs?

I don't see why you say you know how to deal with other molecules, but you think this particular molecule is different.

I'm not saying that, I'm asking how they first got the bond angles for an atom with 4 bond pairs, I'm just giving methane as an example.

 

[Borek]

Sorry, I still fail to see where the problem is.

You know how to calculate angle for atom bonded to two other atoms. Can you explain how it is done?

You know how to calculate angle for atom bonded to three other atoms. Can you explain how it is done?

 

[Comeback City]

The C-H bonds want to be as far apart from each other as possible, as is stated by VSEPR, so they spread out to that 109.5 °. If you are asking why it is 109.5, then https://www.khanacademy.org/science...d-orbitals-jay/v/tetrahedral-bond-angle-proof

 

[Borek]

The C-H bonds want to be as far apart from each other as possible, as is stated by VSEPR, so they spread out to that 109.5 °. If you are asking why it is 109.5, then

We don't know what he is asking. That's what I am trying to find out.

 

[Comeback City]

We don't know what he is asking. That's what I am trying to find out.

Good call

 

[IDK10]

The C-H bonds want to be as far apart from each other as possible, as is stated by VSEPR, so they spread out to that 109.5 °. If you are asking why it is 109.5, then https://www.khanacademy.org/science...d-orbitals-jay/v/tetrahedral-bond-angle-proof

That link helped, thanks.