1.4.2 Ionic Bonding

• As a general rule, metals are on the left of the periodic table and nonmetals are on the right-hand side
• Ionic bonding involves the transfer of electrons from a metallic element to a non-metallic element
• Transferring electrons usually leaves the metal and the non-metal with a full outer shell
• Metals lose electrons from their valence shell forming positively charged cations
• Non-metal atoms gain electrons forming negatively charged anions
• Once the atoms become ions, their electronic configurations are the same as a noble gas
  • A potassium ion (K⁺) has the same electronic configuration as argon: [2,8,8]⁺
  • A chloride ion (Cl^-) also has the same electronic configuration as argon: [2,8,8]^-

Forming cations by the removal of electrons from metals

Forming anions by the addition of electrons to nonmetals

• Cations and anions are oppositely charged and therefore attracted to each other
• Electrostatic attractions are formed between the oppositely charged ions to form ionic compounds
• The ionic bond is the electrostatic attraction formed between the oppositely charged ions, which occurs in all directions ( this called non-directional bonding)
• This form of attraction is very strong and requires a lot of energy to overcome
  • This causes high melting points in ionic compounds

Cations and anions bond together using strong electrostatic forces, which require a lot of energy to overcome

• The ions form a lattice structure which is an evenly distributed crystalline structure
• Ions in a lattice are arranged in a regular repeating pattern so that positive charges cancel out negative charges
• The attraction between the cations and anions is occurring in all directions
  • Each ion is attracted to all of the oppositely charged ions around it

• Therefore the final lattice is overall electrically neutral

Ionic solids are arranged in lattice structures