Transition Elements Flashcards
Which two elements are odd in their electronic configuration?
Copper and chromium
What 3 properties do transition metals have?
Elements of the d-block that have
- partially filled d-orbitals
- can form complexes by coordinate bonding
- have several different oxidation states (both 4s and 3d e- are easily lost as orbitals are very close)
What are copper and chromium’s electronic configuration?
Cu) 3d10 4s1
Cr) 3d5 4s1
What are the oxidation states of manganese?
+2 +4 +7
What is a ligand?
A small molecule with a lone pair that an coordinate bond to a transition metal ion
What shape is a complex with 2 ligands?
Give an example
Linear
Ag(NH3)2 +
What shape is a complex with 4 ligands?
e.g.?
Tetrahedral
(CuCl4)2-
What are the bond angles in a complex with 4 ligands?
109.5°
Complexes with 6 ligands form what shape?
e.g.?
Octahedral
Cu(NH3)4(H2O)2 2+
What colour is aqueous Cu2+ ?
Pale blue
If NH3 (aq) is added to Cu2+ (aq) what is formed and what colour is it?
Cu(NH3)4(H2O)2 2+
Royal blue
When HCl(conc) is added to Cu2+ (aq) what is formed and what colour is it?
(CuCl4)2-
Yellow green
Why are some ions not colourful?
If it has full (Cu+) or empty (Ti4+) d-orbitals then electrons cannot move between energy levels
-> appears colourless/white
What is the colour of aqueous Cr3+?
Green
What is the colour of aqueous Fe2+?
Pale green
What is the colour of aqueous Fe3+?
Yellow
What is the colour of aqueous Cu2+ with NaOH(aq)
Pale blue ppt
What is the colour of aqueous Fe3+ when added to NaOH(aq)
Red brown ppt
What is the colour of aqueous Fe2+ when added to NaOH(aq)
Dark green ppt
What is the colour of aqueous Cr3+ when added to NaOH(aq)
Grey green ppt
Which of these ppts redissolve with excess NaOH (aq) ?
Cr(OH)3 ppt -> (Cr(OH)6)3-
Green solution
Why are transition elements good catalysts?
Their partially filled d-orbitals can form coordinate bonds with reactant molecules.
Their variable oxidation states can reduce or oxidise the reactant to make them more reactive.
3 examples of a transition metal acting as a catalyst?
Iron in the Haber Process
Nickel in the catalytic cracking of hydrocarbons
Vanadium(V)oxide in the contact process
Give two examples of transition metals’ importance in industry
Chromium in stainless steel
Iron in construction
Copper in circuitry and electronics
