Transition Metals Flashcards
Transition Metals
What’s a complex ion
A central metal ion surrounded by ligands
Transition Metals
What’s a ligand
Molecules/ ions which donate a pair of electrons forming coordinate bonds
Transition Metals
What’s a coordinate bond
One of the bonded atoms provide both electrons in the covalent bond
Transition Metals
What’s the vanadium colours and the oxidation states
+2, (V²⁺): purple
+3 (V³⁺): green
+4 (VO²⁺): blue
+5 (VO₄²⁻): yellow
You’d Better Getting Practicing
Transition Metals
What is haemoglobin
Haem is a multidentate ligand that is found in the molecule haemoglobin
It’s a protein and used to transport oxygen around the body in blood
Transition Metals
What happens when electrons absorb light
- They move from the group state to the excited state
- the side of the energy change depends on the central ion and oxidation state and the coordinate number
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Why are 3+ metal aqua ions more acidic than 2+ metal aqua ions
Because the metal aqua ion have a higher charge it’s more polarising to the surrounding bonds this makes it easier to loose the O - H bond in water
Transition Metals
What are the Chromium oxidation state colours
+2 : blue
+3 : green
+4 : colourless
+5 : colourless
+6 : orange
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What is tollens reagent
It contains the silver transition metal which forms a complex ion which is used to distinguish between aldehyde and ketones
Transition Metals
What are amphoteric metal hydroxides
Metal hydroxides that can act as an acid or base which means they are amphoteric
Transition Metals
What does adding a small amount of ammonia to metal aqua ions do
Adding a small amount of ammonia to a metal aqua ions forms a metal hydroxide precipitate
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What does adding excess ammonia to metal aqua ions do
Leads to ligand exchange
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How does haemoglobin transport oxygen
Haemoglobin has a water molecule bonded to it which the oxygen molecule easily replaces and when it gets to where it needs to it breaks off
Transition Metals
Why is breathing carbon monoxide (CO) dangerous
The CO molecule replaces the water ligand on the haemoglobin and it bonds strongly to the haemoglobin so oxygen can’t easily replace it and so O2 can’t be transported
Transition Metals
test for cooper (II) ions
- ammonia
add excess ammonia and a dark blue precipitate will form
[Cu(NH3)4]+2(aq) - sodium hydroxide
by adding sodium hydroxide a light blue precitate will form
Cu2+ + 2OH − →Cu(OH)2(s)
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when is a yellow precipitate formed with hexaaqua copper(II) ions
when hexaaqua copper(II) reacts with concentrated chloride to form tetrachloride copper(II) is formed
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what is ligand substitution
its where one ligand is replaced by another ligand
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how does different sized ligands affect a complex ion
if the ligand that is replacing another ligand is bigger there would be less coordinate bonds round the central metal
(e.g. chloro ligands can only bond 4 times to copper)
Transition Metals
what affects the amount of coordinate bonds
- the size of the ligand
- the amount of coordinate bonds a ligand can form (e.g. bidentate ligands)
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what makes affects feasibility in a ligand substitution reaction
- when ligands are replaced by those that form more co-ordinate bonds there is a significant increase in entropy
- when ligands are replaced by those that form less co-ordinate bonds there is a decrease in entropy
- if there is an entropy decrease the bonds wont be feasible as ΔH is most times negligible
Transition Metals
why do metal complex ion become harmless when reacted with EDTA
EDTA is a chelating agent these are good at bonding to metal ions and difficult to remove this makes the metal ions harmless as it cant bond to anything else
Transition Metals
what is a chelating agent
these are ligands that form more than one coordinate bond and are very good at bonding to metal ions
Transition Metals
what is the ΔH in many ligand substitution reactions and why
the ΔH is negligible in many of these reactions as the same number of bonds are being broken and formed
Transition Metals
what is the chelate affect
in general ligand substitution reactions where ligands are replaced by those that form more co-ordinate bonds the reaction is feasible and this is driven by an entropy increase