Transition Metals Flashcards
Characteristics of TM:
- form complex ions
- formation of colored ions
- variable oxidation states
- catalytic activity
Why is Zn not a TM?
Zn can only form +2 ions, has a complete d subshell so doesn’t meet TM criteria of incomplete d orbital
Complex meaning:
a central metal ion surrounded by ligands
Ligand:
an atom, ion or molecule which can donate a lone electron pair
Heterogenous catalyst v homogenous:
- hetero: diff state to the reactants
- homo: same state to reactants
3 steps in heterogenous catalysis:
Adsorbtion:
* reactants adsorb by forming bonds w atoms at the active sites on the surface of catalyst
Bond breaking and making
* as a result bonds in the reactants are weakened and break followed by bond making
Desorbtion
* this in turn weakens bonds betw/ product and catalyst and product leaves
Poisoning catalysts:
- catalysts can become poisoned by impurities so reduced efficiency
- cost implications
- leaded petrol cant be used in catalytic converter cars since strongly adsorbs onto surface of catalyst
autocatalysis:
the product of the reaction is the catalyst for the reaction
How would you distinguish between seperate samples of 2 stereoisomers (2)
- plane polarised light
- enantiomers would rotate light in opposite directions
2 ways TM different from G1: (2)
- TM can from coloured compounds
- TM have variable OS so can form different compounds
- exist as complex ions
- are good catalysts
Explain why the reaction forms a racemic mixture: (3)
- planar carbonyl group
- attacked from both sides
- with equal probability
Why a solution containinf Fe3+ hex ions has a lower pH than Fe2+ hex ions (3)
- Fe3+ ions have a larger charge to size ratio
- Fe3+ ions are more polarising
- more OH bonds break so more H+ ions released
Difference between Lewis and Bronsted Lowry
- BL base is a H+ acceptor
- BL acid: H+ donor
- Lewis base: e- pair donor
- Lewis acid: e- pair acceptor
