Differentiating Atoms, Molecules, and Ions

• Molecules are combination of two or more atoms connected together by a strong force of interaction. They behave as a single particle.
• Elements that exist not as atom but as molecules:

  1. Hydrogen (H2)
  2. Oxygen (O2)
  3. Nitrogen (N2)
  4. Fluorine (F2)
  5. Sulfur (S8)
  6. Phosphorus (P4)
• Ions - charged atom or molecule formed from gain/loss of electron/s
• Cations are positively charged ions
• Anions are negatively charged ions
• Classification of Ions:

  1. Monoatomic Ions - atoms gain or lose electrons - metals form cations and nonmetals form anions
  2. Multivalent Ions - more than one charge creating several cations
  3. Polyatomic Ions - ions that contain more than one type of atom - held together by covalent bonds
• Ionic Compounds - combination of cations and anions - held together by strong electrical forces between the oppositely charged ions - NaCl
• electrolytes - because ions are charged particles, the solution conducts electric current