When a bond between 2 or more elements is formed, there may be a slight pull of the electrons in the bond toward the more electronegative element which results in a polar molecule. Today we learned how to determine whether or not a bond is polar.
In the molecule above, flourine (F) has the greatest electronegativity which can be found on the periodic table. Because of this, the electrons are pulled toward it and cause an unequal distribution of charge. F has a slightly negative charge as noted by delta minus because is has to negatively charged electrons closer to it. This unequal distribution in charge causes a dipole moment, which is represented by the arrow above the molecule as shown above, The dipole moment points towards the more electronegative atom. In a molecule containing a single bond is automatically polar if it has a dipole moment, like the HF molecule shown above. Dipole moments do not always mean polar in molecules involving multiple bonds, however.
For example, the CO2 molecule contains dipole moments but is not considered polar. The oxygens are the more electronegative atoms, so the dipoles point outwards. These 2 dipoles are in the completely opposite directions, so they cancel each other out, making the molecule nonpolar.
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