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Writing Formulae - Coggle Diagram
Writing Formulae
POSITIVE IONS
Na⁺, K⁺, H⁺
Mg²⁺, Ca²⁺
Al³⁺
NH₄⁺
NEGATIVE IONS
• SO₄²⁻, CO₃²⁻
• OH⁻, NO₃⁻
• O²⁻
• Cl⁻, Br⁻
WHAT IS A FORMULA?
Elements present
Number/ratio of atoms
H₂O = 2H : 1O
REMEMBER
• Check total charge = 0
• Small number = subscript
• Don't change ion charges
BALANCING CHARGES
• 2Al³⁺ + 3O²⁻ → Al₂O₃
• Mg²⁺ + 2Cl⁻ → MgCl₂
• Overall charge = 0
COMPOUND IONS
• Ca²⁺ + 2OH⁻ → Ca(OH)₂
• Use brackets when >1 needed