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Chemistry · Chapter 1: Ionic formulas and names

Year 11 Science · About 15 minutes with activities · Turn your sound on

Chapter 1 · Ionic formulas and names
AlO or Al₂O₃?where do the 2 and 3 come from?
Subscript2 hydrogen atoms
WaterH₂O: 2 H, 1 O
Hydrogen peroxideH₂O₂: toxic
Na⁺: charge +111 protons, 10 electrons
S²⁻: charge −216 protons, 18 electrons
Carbonate ionCO₃²⁻ acts as one unit
Sulfideone sulfur atom
Sulfatesulfur + 4 oxygens
Metal loses e⁻becomes Na⁺
Non-metal gains e⁻becomes Cl⁻
Ionic bonding+ and − ions attract
+ your table of ionson the resource sheet
Ion-card builderadd ions until the charges cancel

Chapter 1 recap

  • Subscripts count atoms, a number outside brackets multiplies what’s inside, a coefficient multiplies everything, and a superscript shows an ion’s charge.
  • In an ionic formula the total positive charge = total negative charge. Positive ion first; no charges showing (Al³⁺ + O²⁻ → Al₂O₃).
  • Brackets only when you need more than one polyatomic ion: Al(OH)₃ but MgCO₃. Name the metal first, then the negative ion (-ide for single atoms): iron(III) chloride.
  • Next: Chapter 2 · Word and balanced equations

Why is it Al₂O₃ and not AlO?

Chapter 1 · About 15 minutes · sound on

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