Final answer:
In a polar covalent bond, the atom with greater electronegativity acquires a partial negative charge (δ-), while the other atom has a partial positive charge (δ+), as seen in the HCl molecule.
Step-by-step explanation:
In a polar covalent bond, the more electronegative atom has a partial negative charge, which is indicated by the Greek letter delta (δ-) and the other atom has a partial positive charge, indicated by δ+. The distribution of electron density in a polar bond is uneven, with the more electronegative atom attracting the electrons more strongly and thus acquiring the partial negative charge.
For example, in a molecule like hydrogen fluoride (HF), fluorine is more electronegative than hydrogen. As a result, the fluorine atom attracts the shared electrons closer to itself, causing a partial negative charge on the fluorine (δ-) and a partial positive charge on the hydrogen (δ+). This charge asymmetry imparts polarity to the molecule.
The concept of polar covalent bonds is crucial in understanding the properties of molecules, such as their solubility, boiling points, and intermolecular forces. Additionally, it plays a key role in explaining the behavior of various substances in chemical reactions and their interactions in biological systems.