Molecular Shape Determines Polarity

The shape of a molecule literally decides everything about it. Think of the electron

pairs around an atom. They're all negatively charged, so they repel each

other, trying to get as far apart as possible. This repulsion forces the molecule into

a specific 3D shape. This shape then determines if the molecule is polar. Water,

for example, has a bent shape. This makes it polar, like a tiny magnet. But carbon dioxide

is a straight line, so even though its bonds are polar, they cancel each other out,

making the whole molecule nonpolar. It's all about geometry.