Polar Covalent Bond: unequal sharing of e-. The nucleus of one atom has a stronger attraction for the shared electrons than the nucleus of the other atom. Therefore, that atom will have a more negative charge, while the other atom will have a more positive charge.
Example:
Polarity of a molecule will determine whether or not it will dissolve in water.
c) Hydrogen Bond : the weak attraction of a hydrogen atom to a nearby oxygen nitrogen or fluorine atom. The polar covalent bonds between hydrogen and either F, O or N results in hydrogen being slightly positively charged When this positive hydrogen atom interacts with a free electron pair on the negatively charged F, O or N a hydrogen bond is formed Hydrogen bonds are approx. One-tenth as strong as covalent bonds, however, their true strength lies in number Hydrogen bonds may occur between atoms in neighbouring molecules or between atoms in different parts of the same molecule Hydrogen bonds are important in biological systems (they define the properties of water and define the structure of DNA)
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