5.3 TRANSITION METALS Flashcards
State the two types of precipitation reactions transition metals can undergo
1) Sodium hydroxide + transition metal
2) Ammonia + transition metal
State the colour of Cu2+ / Copper solution
- Blue
State the colour of Fe2+ / Iron(II) solution
- Green
State the colour of Fe3+ / Iron(III) solution
- Yellow
State the colour of Mn2+ / Manganese solution
- Pink
State the colour of Co2+ / Cobalt solution
- Pink
State the colour of Cr3+ / Chronium solution
- Green
State the observation of Cu2+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Blue precipitate forms
- no change with excess NaOH
State the observation of Fe2+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Green precipitate forms
- No change with excess NaOH
State the observation of Fe3+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Brown precipitate forms
- No change with excess NaOH
State the observation of Mn2+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Brown precipitate forms
- No change with excess NaOH
State the observation of Co2+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Blue precipitate forms
- No change with excess NaOH
State the observation of Cr3+ with dropwise then excess aqueous NaOH/ Sodium hydroxide
- Green precipitate forms
- Precipitate dissolves in excess NaOH
State the observation of Cu2+ with dropwise then excess aqueous NH3/Ammonia
- Blue precipitate forms
- Deep blue solution forms with excess NH3
State the observation of Fe2+ with dropwise then excess aqueous NH3/Ammonia
- Green precipitate forms
- No change with excess NH3
State the observation of Fe3+ with dropwise then excess aqueous NH3/Ammonia
- Brown precipitate forms
- No change with excess NH3
State the observation of Mn2+ with dropwise then excess aqueous NH3/Ammonia
- Brown precipitate forms
- No change with excess NH3
State the observation of Co2+ with dropwise then excess aqueous NH3/Ammonia
- Blue precipitate forms
- No change with excess NH3
State the observation of Cr3+ with dropwise then excess aqueous NH3/Ammonia
- Green precipitate forms
- Purple solution forms with excess NH3
Define transition element
- A d-block element that has an incomplete d-sub-shell when a stable ion
State the two elements are not classed as a transition element/metal
- Zinc Zn2+
- Scandium Sc3+
State the electron configuration to explain why scandium 3+ is not a transition element/metal
- Scandium’s d-orbital is empty
State the electron configuration to explain why zinc 2+ is not a transition element/metal
- Zinc’s d-orbital is full/complete
Give two examples of transition metals as catalysts
1) MnO2 catalyses the decompostion of H202
2) Cu2+ catalyses the reaction of Zn with acids
Give two examples of transition elements with variable oxidation states
1) Fe2+ and Fe3+
2) Cr2+ and Cr3+ and Cr6+
State an advantage and disadvantage of using transition metals as catalysts
- Reduces energy usage which improves profits
- However, they are toxic
Define complex
- A central metal ion surrounded by ligands
Define ligand
- An atom, ion or molecule which can donate a lone pair of electrons
State the type of bonding used in complex formation
- Co-ordinate/dative covalent
Define co-ordination number
- The number of co-ordinate bonds formed to a central metal ion
Define bidentate ligand
- A ligand that donates two electron pairs to a metal ion to form two co-ordinate bonds with the metal ion
Define monodetate ligand
- A ligand that donates one electron pair to a metal ion to form one co-ordinate bond with the metal ion
Draw the two optical isomers of the complex ion ethandioate and state the co-ordinate number
- 6
Draw the two optical isomers of the complex ion and state the co-ordinate number
- 6
State what is required for cis-trans isomerism in square planar complexes
- Four ligands where two are the same and the other two are the same
State what is required for cis-trans isomerism in octahedral complexes
- Six ligands where four are the same and the other two are the same
State what is required for optical isomerism in octahedral complexes
- Three bidentate ligands
Describe the advantages and disadvantages of the use of cisplatin
- Anti-cancer drug used in chemotherapy
- Binds to the DNA in cancer cells to prevent division and stop cancer
- However can cause hairloss, sickness and fatigue if it binds to healthy cells
Define ligand substitution
- A reaction where one ligand is substituted for another ligand in a complex ion
Explain the importance of iron in haemoglobin in terms of ligand substitution
- O₂ is a ligand that datively/co-ordinately bonds with Fe²⁺ so that oxygen can be carried in the blood
- When required, O₂ is released
Explain why carbon monoxide is toxic in terms of ligand substitution
- CO is a ligand that datively/co-ordinately bonds with Fe²⁺ in haemoglobin
- These are stronger than the ones O₂ forms with Fe²⁺ in haemoglobin
- This prevents O₂ from bonding to it
State the three typical reaction of transition metals
1) Percipitation
2) Ligand substitution
3) Redox
Draw out all the reactions of iron as a transition metal
Draw out all the reactions of copper as a transition metal
Draw out all the reactions of chronium as a transition metal
Draw out all the reactions of cobalt as a transition metal
Draw out all the reactions of manganese as a transition metal
Test for Cu²⁺ ions
- Cu²⁺ is a blue solution
- Dropwise NH₃ or OH⁻ produces a blue percipitate
- Excess NH₃ dissolves the blue percipitate to form a blue solution
- No change with excess OH⁻
Test for Fe²⁺ ions
- Fe²⁺ is a green solution
- Dropwise NH₃ or OH⁻ produces a green percipitate
- No change with excess NH₃
- No change with excess OH⁻
Test for Fe³⁺ ions
- Fe³⁺ is a yellow solution
- Dropwise NH₃ or OH⁻ produces a brown percipitate
- No change with excess NH₃
- No change with excess OH⁻
Test for Mn²⁺ ions
- Mn²⁺ is a pink solution
- Dropwise NH₃ or OH⁻ produces a brown percipitate
- No change with excess NH₃
- No change with excess OH⁻
Test for Cr³⁺ ions
- Cr³⁺ is a green solution
- Dropwise NH₃ or OH⁻ produces a green percipitate
- Excess NH₃ dissolves the green percipitate to form a purple solution
- Excess OH⁻ dissolves the green percipitate to form a green solution
Test for NH₄⁺
- Add NaOH and gentle warming
- Distinctive ammonia gas smell will turn red litmus paper into blue
Test for CO₃²⁻
- Add strong acid
- Produces carbon dioxide gas which turns limewater cloudy
Test for SO₄²⁻
- Add barium chloride
- A white percipitate of barium sulfate forms
Test for Cl⁻,Br⁻,I⁻ ions
State in which order 4s electrons are added and removed
- added first and removed first