A2: Transition Metals Flashcards
Define “Complex Ion”
- central metal ion
* surrounded by CO-ORDINATELY BONDED LIGANDS
Define “Co-ordination Number”
the NUMBER of CO-ORDINATE bonds formed to a Central Metal I🍩N
Define “Ligand”
an ATOM, ION or MOLECULE that can DONATE 🐮 a LONE electron PAIR
3 characteristics of Transition Metals:
- 🐱 Catalysis
- VOS Variable Oxidation States
- C🔴L🔵URED I⚫️NS
Why are Transition Metal Ions usually coloured?
- ONE C🔴L🔴UR of LIGHT 🔦 is ABSORBED to EXCITE 🙈🙉 the electron
- remaining C🔵L🔵UR is TRANSMITTED through the SOLUTION
Name of ligand that can form 2 co-ordinate bonds and example?
- bidenTate
* NH2CH2CH2NH2
Define “Transition Metal”
partially filled
🍆D
shell 🐚
One feature of SILVER Chemistry that is NOT a feature of Transition Metals:
colourLESS ⚪️
Give an example of a MULTIDENTATE ligand:
EDTA 4-
elizabeth
dona
tames
alan
Alternative analytical method for determining the concentration of a solution?
ATOMIC
ABSORPTION
Electronic Config. of Copper Atom (29 electrons)
1s2, 2s2, 2p6, 3s2, 3p6
3d10, 4s1
Electronic Configurations for Transition Metals
2 rules
When filling up: always 4s1 then 3d…
When removing, always remove everything from 4s shell first
Define “Bi-dentate”
forms 2⃣ co-ordinate bonds 💗
Example of a LINEAR complex formed by a transition metal:
● [AgCl2] -
● [Ag (NH3)2]+
Formula for Tollen’s and what does it do?
- [Ag(NH3)2]+
* used to distinguish between aldehydes and ketones
Define HETEROgeneous:
in a diff. PHASE 💭
Why may any impurities in reactants cause problems whilst using Heterogenous Catalysts:
might BLOCK 🚫 Active 💃 Sites
Define “Autocatalysed”
catalyst 🐱 is a reaction PRODUCT
why are the complexes different C🔴L🔵URS?
- different LIGAND
- different D orbital energy
- different wavelengths of COLOURS of light 🔦 are absorbed by d electrons
- different wavelengths of COLOURs of 🔦 are REFLECTED
Planck Constant’s Equation
🔺E = hv
Units for “Frequency of Visible Light”
Hz
Features of Transition Metal Complexes that cause a change in the 🔺E value:
- IDENTITY of ligand
- IDENTITY of metal
- CHARGE on the METAL
Define “Oxidising Agent”
GAINS electrons and gets REDUCED
Define “Reducing Agent”
DONATES electrons and gets OXIDISED
In 🔺E = hv, what do the symbols E and h stand for?
- E = energy absorbed by electron
- h = Planck’s constant
Physical properties of transition metals?
- High density
- High BP and MP
- Ionic Radius more or less the same
Why is acid added to the REDUCING agent in redox TITRATIONS?
to make sure there are plenty of H+ ions to allow all the oxidising agent to be REDUCED
What are the two main OXIDISING agents used in redox titrations?
- MnO4-1 (purple)
- Cr2O72- (orange)
Why do Transition metals make good catalysts?
- they have VARIABLE OXIDATION STATES
- meaning they can TRANSFER electrons
- to SPEED up reactions
The Contact process is used to make….?
SULFURIC ACID
Write an equation for the Contact Process:
S02(g) + 1/2 O2(g) (V205 catalyst (s)—> SO3
List 3 HETEROgeneous Catalysts and their uses:
- Iron (s) (Haber Process)
- V205 (s) (Contact Process)
- Cr203 (s) Manufacture of METHANOL from Carbon Monoxide and Hydrogen
Write an equation for the Haber Process:
N2 + 3H2 (Fe catalyst (s)—> 2NH3
Write an equation for the manufacture of METHANOL:
CO + 2H2 (Cr203 catalyst (s)—> CH3OH
Define “Catalyst Poisoning”:
IMPURITIES in a reaction mixture may bind to the catalyst’s SURFACE and BLOCK REACTANTS from being ADsorbed - less SA available for reactants so reactions SLOWS down
List 2 examples of Catalyst Poisoning
- LEAD coats the SURFACE of catalyst in CATALYTIC CONVERTERS so vehicles with catalytic converter must only be run on unLEADed petrol
- SULFUR poisons the IRON catalyst in the Haber Process (H2 in Haber process comes from METHANE which comes from a NATURAL gas containing IMPURITIES e.g. Sulfur)
How can catalyst poisoning be reduced?
by PURIFYING the reactants
How many humps are present in the ENERGY PROFILE for a HOMOgeneously catalysed reaction and why?
2
bcos FIRST: reactants combine with catalyst to make an INTERMEDIATE species
SECOND: the INTERMEDIATE species forms the PRODUCTS and REFORM the catalyst
Show how Fe2+ catalyses the reaction between S208 2- and I-
S208 2- + 2I- —> I2 + 2S04 2-
