Transition Metals Flashcards
Define transition metal
Elements with a partially full d sub shell that can form at least 1 stable ion with a partially full D sub shell
List some properties of transition metals
Formation of complexes
Formation of coloured ions
Variable oxidation states
Ability to act as a catalyst
Good conductors of heat and electricity
What elements don’t fill up 4s sub shell first
Cooper ( 3D5 4S1)
Chromium (3D10 4S1)
Why are scandium and zinc not considered to be transition elements
Scandium only forms 3+ ions, with no electrons in d sub-shell
Zinc only forms 2+ ions (3D10)
What’s the catalyst for Haber process, hydrogenation of vegetable fats
Iron (heterogeneous)
Nickel (heterogeneous)- product margarine
What are the catalysts used for decomposition of hydrogen peroxide, the contact process and (iodine ions and peroxodisulfate ions)
Manganese dioxide (heterogeneous)
Vanadium oxide (hetero)
Iron (homo)
What are monodentate ligands, give some examples
Have 1 pair of electrons that can be donated to form a coordinate bond
Water, ammonia
What are bidentate ligands, give example
Donate 2 pairs of electrons to the central atom
NH2CH2CH2NH2, C2O42-
what is the importance of iron in haemoglobin
Haem is part of haemoglobin responsible for carrying oxygen, has a central Fe2+ with a coordination number of 6,
O2 gas act as a ligand and binds to haem molecules, O2 is poor ligand and easily released from molecule to body cell that needs it
why is carbon monoxide a poisonous gas
it is a better ligand than O2 so binds strongly to haem molecule, it can irreversibly bind to haem and prevent O2 being carried to cells
give the shape, bond angle and example with coordination numbers of 2
linear, 180degree, [Ag(NH3)2] +
give the shape, bond angle and example with coordination numbers of 4 (large ligand complexes)
tetrahedral, 109.5 degree, [CuCl4]2-
give the shape, bond angle and example with coordination numbers of 4 (Pt2+ complexes)
square planar, 90 degree, [PtCl4]2-
give the shape, bond angle and example with coordination numbers of 6
octahedral, 90degree, [Cu(H20)6]2+
when can octahedral ligands ONLY show cis/trans stereoisomerism
with monodentate ligands
when can octahedral ligands show cis/trans isomerism and optical isomerism
with bidentate ligands
how can only cis isomers have optical isomers as well
trans: top and bottom the same, so the 2 on the side form bidentate ligands
Cis: top and (one to the left): bottom and bottom left form bidentate ligand and the 2 on the right,
top and (one to right): bottom and bottom right form bidentate ligand, 2 on left
describe the difference between cis and trans platin
Cis: both Cl on same side, both NH3 on same side
trans: one Cl and one NH3 on same side
why does only cis platin work as a drug
only cis can bind to DNA to prevent cell division to stop cancer
what happens to the coordination number when ligand substitution reactions occur between non charged ligands (ammonia and water)
no change in coordination number
what happens when Copper II sulfate in water [Cu(H20)6]2+, reacts with ammonia
light blue–> dark blue
[Cu(NH3)4(H20)2]2+ forms
what happens when Copper II sulfate in water [Cu(H20)6]2+, reacts with concentrated HCl
pale blue–> yellow
[CuCL4]2-
describe the ligand substitution between [Cr(H20)6]3+ with excess ammonia
1: violet–> grey-green Cr(OH)3
2: dissolves in excess ammonia to form purple solution [Cr(NH3)6]3+
give the full equation between [Cr(H20)6]3+ with excess ammonia
[Cr(H20)6]3+ + 6NH3—-> [Cr(NH3)6]3+ + 6H2O
give full equation of [Cu(H2O)6]2+ with excess sodium hydroxide, then full equation with [Cu(H2O)6]2+ and ammonia
pale blue—>blue precipitate forms
[Cu(H2O)6]2+ + 2OH- —> Cu(H2O)4(OH)2 + 2H2O
[Cu(H2O)6]2+ + 2NH3–> [Cu(H2O)4(OH)2] (s) + 2NH4+
[Cu(H2O)4(OH)2] + 4NH3–> [Cu(H2O)2(NH3)4]2+ + 2H2O + 2OH-
give the equation between [Fe(H2O)6]2+ with excess sodium hydroxide, then full equation with [Fe(H2O)6]2+ and ammonia
pale green—> green precipitate forms
[Fe(H2O)6]2+ + 2OH- —> Fe(H2O)4(OH)2 + 2H2O
[Fe(H2O)6]2+ 2NH3–> Fe(H2O)4(OH)2 + 2NH4+
give the equation between [Fe(H2O)6]3+ with excess sodium hydroxide, then full equation with [Fe(H2O)6]2+ and ammonia
pale yellow—>orange/brown precipitate forms
[Fe(H2O)6]3+ + 3OH- —> Fe(H2O)3(OH)3 + 3H2O
[Fe(H2O)6]3+ 3NH3–> Fe(H2O)3(OH)3 + 3NH4+
give the equation between [Mn(H2O)6]2+ with excess sodium hydroxide, then full equation with [Mn(H2O)6]2+ and ammonia
pale pink—> light brown precipitate forms
[Mn(H2O)6]2+ + 2OH- —> Mn(H2O)4(OH)2 + 2H2O
[Mn(H2O)6]2+ 2NH3–> Mn(H2O)4(OH)2 + 2NH4+
give the equation between [Cr(H2O)6]3+ with excess sodium hydroxide, then full equation with [Cr(H2O)6]2+ and ammonia
violet—> grey/green precipitate forms
[Cr(H2O)6]3+ + 3OH- —> Cr(H2O)3(OH)3 + 3H2O
[Cr(H2O)6]3+ 3NH3–> Cr(H2O)3(OH)3 + 3NH4+
Cr(H2O)3(OH)3 +6NH3—> [Cr(NH3)6]3+ + 3H2O + 3OH-
in the redox titration between Iron III and acidified manganate IV ions, what are the products and colour changes
purple manganate IV ions reduced to II ions (colourless)
Orange/brown iron III ions reduced to pale green iron II ions by reaction with iodide ions, iodide forms a brown colour
how can chromium ions be oxidised and reduced to dichromate ions
green chromium III oxidised by hot alkaline hydrogen peroxide to orange dichromate VI ions
reduction: dichromate VI ions back to chromium III ions by acidified zinc
what is the colour for all Cu2+/Cu+ complexes
[Cu(H2O)6]2+: pale blue
[Cu(NH3)4(H20)2]2+: dark blue
[CuCL4]2-: yellow
Cu(OH)2: pale blue precipitate
Cu+ (reduction of Cu2+ and I-): white precipitate (CuI) and brown I2
Cu2+/Cu: Cu+ brown solid and blue solution
what is the colour for Co2+
CoCl4)2-(from CoCl2.6H2O and excess HCl): blue
what are the colours for Cr
[Cr(H2O)6]3+: pale purple (due to impurities common to appear green)
[Cr(NH3)6]3+: purple
Cr(OH)3: dark green precipitate
[Cr(OH)6]3-: dark green
Cr2O7/2-: orange
CrO4/2-: yellow
what are the colours for manganate
[Mn(H2O)6]2+: pale pink
Mn(OH)2: pale brown precipitate
what are the colours for iron
[Fe(H2O)6]2: pale green
[Fe(OH)2]: dark green precipitate
[Fe(H2O)6]3+: yellow
[Fe(OH)3] : orange/brown precipitate
give the colour change of MnO4-/Fe2+–>Mn2+/Fe3+
purple–>pale pink (in titrations so dilute practically colourless)
give the colour change of I-/Fe3+—>I2/Fe2+
orange/brown—> brown
