Chemistry polarity and bond angles on molecules


I am in Chem 2 and I dont know what I am not understanding about polarity and bond angles of molecules so I would like some answers lol. Like what makes molecules polar or nor polar in specific. Thanks in advance!

In: 1

Polarity cones from electro negativity of the atoms involved.

H2O, oxygen is more electro negative than hydrogen so attracts the electrons closer, hence we started g dipole moments.

2 water molecules will try and align themselves accordingly, and 1 oxygen will bind to it’s own, but is also attracted to the hydrogen of the otherwatwr molecule.

Put a bunch of water molecules together and they will reorganize accordingly.

Specifically I start to think of it in terms of symmetry. Water is polar, methane (CH4) is not. On the Y axis, each half of a water molecule is half an oxygen atom, and one hydrogen atom. It’s symmetric. On the X axis, you have an oxygen atom, or two hydrogen atoms. Not symmetric. Therefore, it’s a polar molecule. Methane is always symmetrical, so non-polar. After that we start driving into electronegativity… But that’s a bit deeper and I’m on a phone.

Imagine a hydrogen atom, a proton with a circling electron. It has a net zero charge *over all* but the electron and proton are separate things. Imagine I grabbed the electron and glued it in place to the left of the proton, now you have a (-) side on the left where the electron is and a (+) side on the right where the proton is. This is called “polarity” and it’s kind of similar to the north/south poles on a magnet, only using electric charge in lieu of magnetism.

Now imagine a water molecule, the oxygen atom pulls on the hydrogen’s electrons and holds them close, just like the example above. So now the side of the hydrogen atom that’s closest to the oxygen atom is the (-) charge and the side that’s opposite the oxygen has the (+) charge. Similarly, presence of the hydrogen’s electrons repels the oxygen’s existing electrons away to the opposite side. So a water molecule is polar, meaning the hydrogen side is slightly positive and the oxygen side is slightly negative. This polarity is pretty powerful and part of the reason why water things like salt love dissolving in water, the water’s polarity is powerful enough to tear the salt molecule apart.

Bond angles are related to polarity. The various (-) and (+) parts of a molecule all push and pull on each other and eventually establish a balance.