A Hydrated Ion in Solution

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Explain what is meant by a hydrated ion in solution

• When an ionic compound dissolves in water
  • Ions dissociate
  • Ions are surrounded by water molecules
• These ions are said to be hydrated
• They are represented by
  • Mⁿ⁺
  • X^y-
• Water molecules orient themselves so that
  • Their positively charged end (the hydrogen’s) faces the anions
  • Their negatively charged end (The oxygen) faces the cations
• This process is hydration
• Many cations are surrounded by a fixed number of tightly bound water molecules
  • g Fe³⁺ is surrounded by six water molecules and becomes [Fe(H₂O)₆]³⁺
  • The charge on the complex remains unchanged