Question #2cff6

1 Answer
Nov 16, 2016

This results from electronegativity and causes polarity.


Different atoms have different values for electronegativity. Electronegativity is really a measure of how strongly an atom will pull/attract electrons to itself when it's participating in a covalent bond.

If an atom with a higher electronegativity combines with an atom with a lower electronegativity covalently, then the following will occur. (Focus on the shape of the molecule to the bottom left)

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Let's use HCl as an example. Cl is more electronegative than H. This means that Cl will pull the shared electrons to itself more strongly than H will. This causes the electrons to be shared unevenly in the covalent bond.

Look at this image.

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Recall that eletrons are negatively charged particles. If Cl is pulling them more strongly, then they will be closer to that end of the molecule. Hence, Cl will obtain a slight #delta^-# charge. Since the electrons have moved further away from H, it will obtain a slight #delta^+# charge.

This is polarity. Both atoms in the molecule have become slightly charged due to the uneven sharing of electrons within the covalent bond.