Polarity

Polarity

Every molecule is depicted as either polar or nonpolar. These terms just mean whether or not a molecule has an even distribution of electrons throughout. Polar means that there is an uneven distribution of electrons throughout the molecule. For example the molecule H2O is a polar molecule due to the excess electrons that are not being used by the Hydrogen. Nonpolar means that there is an even distribution of electrons throughout the molecule. This means that the hydrogen have a more positive charge while the Oxygen has a more negative charge. ClF4 is an example of a molecule that has an even distribution of electrons as although they have unused electrons, every single Fluorine has six unused electrons. This means that no atom is more negative than any other.

Hydrazine, N2H4, is a polar molecule. This is because it has an uneven distribution of electrons in the molecule.

The dash model above shows that although each of the four hydrogen have an even distribution, the two nitrogens do not. The Nitrogens originally contained five electrons, and the Hydrogen only one electron. So, pairing off the single hydrogen electron to one of the single nitrogen electron, a single pair of nitrogen electrons is left over. Each has a pair of electrons that are not being used, causing the uneven distribution. This causes the Hydrogen to be slightly positive where as the Nitrogen has a slightly negative charge.