How Atoms Stick Together

Atoms form bonds to achieve stability, filling their outer electron shells. There are three main types of chemical bonds:

• Ionic Bonds: Transfer of electrons from one atom to another, creating charged ions.
• Covalent Bonds: Sharing of electron pairs between atoms.
• Metallic Bonds: Delocalized electrons shared by a lattice of metal atoms.

Molecular Shapes

The shape of molecules is predicted by the VSEPR (Valence Shell Electron Pair Repulsion) theory, which states that electron pairs arrange themselves to minimize repulsion.

• Linear, trigonal planar, tetrahedral, and bent shapes are common.

Polarity

Molecules can be polar (uneven charge distribution) or nonpolar (even charge). Polarity affects properties like boiling point and solubility.

Everyday Importance

• Explains why salt dissolves in water—ionic compounds interact with polar molecules.
• Determines why oil and water don’t mix due to differences in polarity.