Metal-aqua ions Flashcards
What is a co-ordinate bond?
One substance donating a pair of electrons to another
When do metal-aqua complex ions form?
When metal ions dissolve in water, the water molecules form co-ordinate bonds with the metal ions
In general, how many water molecules bond in a metal-aqua complex?
6
Why are metal 3+ ions more acidic than metal 2+ ions?
- Metal 3+ ions have a higher charge density than metal 2+ ions
- Metal 3+ ions are much more polarising than the 2+ ions
- Metal 3+ ions attract electrons from the oxygen atoms from the co-ordinately bonded water molecules more strongly than the metal 2+ ions
- This means it is more likely an H+ ion will be released and then the solution will be more acidic
What is the general overall equation when metal aqua ions act as bronsted Lowry acids?
[M(H₂O)₆]³⁺ + 3H₂O M(OH)₃(H₂O)₃ + 3H₃O+
What is the first equation when a 3+ metal aqua ion complex reacts with water?
[M(H₂O)₆]³⁺ + H₂O [M(OH)(H₂O)₅]²⁺ + H₃O+
What is the second equation when a 3+ metal aqua ion complex reacts with water?
[M(OH)(H₂O)₅]²⁺ + H₂O [M(OH)₂(H₂O)₄]⁺ + H₃O+
What is the third equation when a 3+ metal aqua ion complex reacts with water?
[M(OH)₂(H₂O)₄]⁺+ H₂O M(OH)₃(H₂O)₃ + H₃O+
What can some metal hydroxides be?
Amphoteric
what does amphoteric mean?
They can act as both acids and bases
What colour is [Cu(H₂O)₆]²⁺?
Blue solution
What colour is [Fe(H₂O)₆]²⁺?
Green solution
What colour is [Fe(H₂O)₆]³⁺?
Yellow solution
What colour is [Al(H₂O)₆]³⁺?
Colourless solution
What is formed when [Cu(H₂O)₆]²⁺ reacts with OH- or NH₃?
Cu(OH)₂(H₂O)₄ + 2H₂O
