The Transition Metals - exam practice

[Cr(NH₃)₄Cl₂]⁺ and [Mn(H₂O)₆]²⁺

CrO₄^2- and TiCl₃

Cr₂O₃ and [Fe(CN)₆]^3-

Cr₂O₇^2- and MnO₄^-

+1

+5

+6

+7

CH₃NH₂

CN^-

NH₃

NH₄⁺

vanadium

chromium

manganese

iron

[Co(NH₃)₆]³⁺

[Co(NH₃)₅(H₂O)]³⁺

[Co(NH₃)₅(Cl)]²⁺

[Co(NH₃)₄(Cl)₂]⁺

it is in the d block of the periodic table

it forms stable ions in which it has different oxidation numbers

it has incompletely filled d orbitals

it forms stable ions which have incompletely filled d orbitals

excited electrons emit light in the blue region of the spectrum as they drop back to the ground state

excited electrons emit light in the red region of the spectrum as they drop back to the ground state

electrons absorb light in the red region of the spectrum and the residual frequencies are observed

electrons absorb light in the blue region of the spectrum and the residual frequencies are observed

the bonding in both complexes is dative covalent

the bonding in both complexes is ionic

the bonding in Pt(NH₃)₂Cl₂ is dative covalent and in CrCl₄^- is ionic

the bonding in Pt(NH₃)₂Cl₂ is ionic and in CrCl₄^- is dative covalent

is square-planar

is tetrahedral

contains a double bond

is octahedral

both reactants can react with Fe²⁺ ions

both reactants can react with Fe³⁺ ions

S₂O₈^2- ions can be oxidised by Fe³⁺ ions and I^- ions can be reduced by Fe²⁺ ions

S₂O₈^2- ions can be reduced by Fe²⁺ ions and I^- ions can be oxidised by Fe³⁺ ions

2

3

4

6

transition metals form coloured ions and complexes

transition metals display variable oxidation states

a ligand accepts a pair of electrons from a transition metal

a complex is a central metal atom or ion surrounded by ligands

Cr₂O₇^2-_(aq)

Fe²⁺_(aq)

Fe³⁺_(aq)

Cu²⁺_(aq)

oxidation state of the metal

number of ligands in the complex

identity of the ligands in the complex

isotope of the metal

identity of the ligand

temperature of the solution

identity of the metal

oxidation number of the metal

the different colours are due to the different charges on the complex

the different ligands cause different splitting in the 3d orbitals

the oxidation state of cobalt is different in each complex

[CoCl₆]^3- absorbs orange light

as electrons are promoted to higher energy levels, light of a certain colour is absorbed, and the complementary colour is observed

as electrons return to lower energy levels, light of a certain colour is emitted, and the complementary colour is observed

as electrons are promoted to higher energy levels, light of a certain colour is absorbed, so the complex appears to have the same colour

as electrons return to lower energy levels, light of a certain colour is emitted, so the complex appears to have the same colour

0

1+

2+

3+

0

1+

2+

3+

[Ne]3s²3p⁶4s¹

[Ar]3d⁹

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p²

[Ar]4s¹3d⁵

Fe²⁺ has many electrons in its outermost subshells

Fe²⁺ has many active sites on which the reaction can occur

Fe²⁺ is readily oxidised to Fe³⁺ which is then reduced to Fe³⁺

Fe²⁺ will reduce sulfate ions to peroxodisulfate ions

coordination number: 2; m = 0

coordination number: 2; m = 4$-$

coordination number: 6; m = 0

coordination number: 6; m = 4$-$