Ionic vs. Molecular (Covalent) Compounds

How to Differentiate Ionic and Molecular Compounds

• Ionic Compounds:
  • Composed of metals and nonmetals
  • Example: Sodium chloride (NaCl)
• Molecular/Covalent Compounds:
  • Composed of only nonmetals
  • Example: Sulfur dioxide (SO2), Water (H2O)
• Exception: Hydrogen is a nonmetal even though it is on the metal side of the periodic table.

Using the Periodic Table

• Metals are located on one side of the periodic table's "staircase"
• Nonmetals are on the opposite side of the "staircase"
• Practice Examples:
  • Molecular: Sulfur dioxide (SO2), Water (H2O), Propanol (C3H8O)
  • Ionic: Sodium chloride (NaCl), Copper(II) fluoride (CuF2), Lithium nitrate (LiNO3), Sodium sulfate (Na2SO4)

Special Cases: Polyatomic Ionic Compounds

• Contain more than two elements
• Examples include lithium nitrate and sodium sulfate

Differences in Bonding

• Molecular/Covalent Compounds:
  • Atoms share electrons
  • Example: Water (H2O) - sharing illustrated as "holding hands"
• Ionic Compounds:
  • Electrons are transferred (one atom steals electrons from another), leading to charged ions
  • Opposite charges attract each other (like magnets)
  • Example: Sodium chloride (NaCl) - chlorine takes an electron from sodium

Structural Differences

• Molecular Compounds:
  • Made of molecules, clumps of atoms
  • Example: Sugar molecules
• Ionic Compounds:
  • Form lattice structures, organized box-like shapes
  • Example: Table salt (sodium chloride)

Behavior in Water

• Molecular Compounds dissolve into molecules
• Ionic Compounds dissolve into individual ions

Additional Resources

• Videos are available for deeper dives into polyatomic ionic compounds and the physical properties and solubility behaviors of ionic and molecular compounds.