Ionic Bonding Overview

Ionic Bonding Overview

• Ionic bonding is an electrostatic attraction between oppositely charged ions.
• This attraction forms when electrons are transferred from one atom to another.
• The strong electrostatic force holds the ionic lattice structure.

Ion Formation

• Cations (Positive Ions): Metal atoms lose electrons, becoming positively charged.
• Anions (Negative Ions): Non-metal atoms gain electrons, becoming negatively charged.
• Losing an electron increases the number of positively charged protons, creating a positive ion.
• Gaining an electron increases the number of negatively charged electrons, creating a negative ion.
  • Examples: Sodium (Na) loses one electron to form Na⁺; Chlorine (Cl) gains one electron to form Cl⁻.

Writing Ionic Formulas

• Write the symbols for the elements.
• Note the valency (electrons gained/lost) above each element.
• Cross-over the valencies as subscripts (ignore any '1's).
• If valencies are the same, they cancel each other out (like in NaCl).
• Roman numerals indicate the charge on an ion when needed (e.g., Fe²⁺).
• Use brackets for multiple compound ions (e.g., CuSO₄).

Ionic Lattice Structure

• Ionic compounds form a giant 3-dimensional repeating structure.
• Ions are arranged in a continuous 3D lattice.
• Example: In sodium chloride (NaCl), each Na⁺ ion is surrounded by 6 Cl⁻ ions, and vice versa.

Ionic Compound Properties

• High Melting/Boiling Points: Strong electrostatic forces between ions require a lot of energy to overcome.
• Conductivity: Solid ionic compounds don't conduct electricity (fixed ions). Molten or dissolved ionic compounds conduct electricity (free ions moving).
• Solubility: Ionic compounds are often soluble in water.

Ions and Isoelectronic Noble Gases

• Ions achieve stable electron configurations (full outer shells) by gaining or losing electrons.
• Isoelectronic ions have the same electron configuration as noble gases.
• Examples: Na⁺ is isoelectronic with Ne; F⁻ is isoelectronic with Ne.

Common Polyatomic Ions

• Chloride (Cl⁻)
• Oxide (O²⁻)
• Sulphate (SO₄²⁻)
• Nitrate (NO₃⁻)
• Iodide (I⁻)

Metal-Nonmetal Bonding

• Ionic bonds form between metals and non-metals due to electron transfer.
• Metals lose electrons to become cations.
• Non-metals gain electrons to become anions.
• The resulting ions achieve a stable electron configuration (isoelectronic with noble gases).

Summary

• Ionic bonding involves electron transfer creating oppositely charged ions.
• The ions form a repeating 3-dimensional lattice.
• Ionic compounds generally have high melting/boiling points and are soluble in water. They conduct when molten or dissolved.
• Ionic formulas represent the ratio of ions in a compound.

Explore the fundamentals of ionic bonding in this quiz. Learn how cations and anions form through electron transfer and how to write ionic formulas correctly. Test your understanding of this essential chemistry topic.