Final answer:
Hydrogen bonds form between slightly positive and slightly negative charges of polar covalent molecules. These bonds are formed when the hydrogen atom in a polar covalent bond has a slightly positive charge and is attracted to neighboring negative charges on other molecules.
Step-by-step explanation:
Hydrogen bonds form between slightly positive (+) and slightly negative (-) charges of polar covalent molecules. When polar covalent bonds containing hydrogen form, the hydrogen in that bond has a slightly positive charge because hydrogen's electron is pulled more strongly toward the other element and away from the hydrogen. This creates weak interactions, called hydrogen bonds, between the positive hydrogen atom and neighboring negative charges on other molecules.