Final answer:
The negative pole of a molecule can be predicted by comparing the electronegativity of the atoms; the more electronegative atom will be the negative pole. This can also be visualized using Lewis structures and VSEPR theory. Polar molecules such as water have a dipole, with negative and positive poles.
Step-by-step explanation:
To predict which side of a molecule will be the negative pole, you need to examine the electronegativity of the atoms within the molecule. The atom with higher electronegativity will attract the bonding pair of electrons more strongly and thus will have a higher electron density. This results in that side of the molecule acquiring a partial negative charge, represented by the symbol δ- (delta minus). Conversely, the atom with lower electronegativity ends up with a partial positive charge, represented by δ+ (delta plus). This creates a dipole with two poles, similar to a magnet which has a north and a south pole. In a molecule like water (H₂O), the oxygen atom has a higher electronegativity compared to the hydrogen atoms and thus the side of the water molecule where the oxygen atom is located becomes the negative pole.
Additionally, molecular polarity can be understood through Lewis structures and VSEPR theory. This method helps in visualizing the molecular geometry and determining if the molecule is polar (asymmetric) or nonpolar (symmetric). A polar molecule has atoms with differing electronegativities or a central atom with lone pairs of electrons. In the presence of an electric field, polar molecules align themselves with the negative pole towards the positive plate and vice versa, indicating the direction of their poles.