5.3.1 Transition element

What is a transition element ?

D block element that forms at least one ion with a incomplete d subshell

Which of the period 4 d-block elements are not transition metals?

Scandium and zinc

what is the electron configuration of Cr

[Ar] 4s¹ 3d⁵

what type of ions do transition metals form

positive ions

how to work out electronic configuration for d block ions ?

remove 4s subshell e⁻

remove 3d subshell e⁻

Why is scandium not a transition element?

Scandium only forms Sc³⁺ which has a empty D subshell

Why is zinc not a transition element?

Only forms Zn²⁺ which has a full D subshell

what are some properties of Transition metals?

Form complex ions

Good catalysts

exist in variable oxidation states

Why do they exist in variable oxidation states?

energy levels of 4s and 3d subshell is similar,

different numbers of e⁻ can be lost or gained using similar energy

Disadvantages of using transition metals catalysts?

compounds and metals are toxic --> cause health risks

name 2 transition metal catalyst and there uses ?

Fe - catalyst in the Haber process

MnO₂ - catalyst in the decomposition of H₂O₂

Advantages of using transition metals catalyst?

allow reactions to happen faster at lower temperatures/pressure -- reduces energy usage.

why do transition metals have special chemistry properties

they have a incomplete d subshell

What is a complex ion?

transition Metal ion surrounded by co-ordinately bonded ligands

What is a ligand?

a ion or molecule that donates e^- to co-ordinately bond to a central metal ion

what is a coordinate bond?

Covalent bond where both electrons are supplied from the same species

what do all ligands have

a lone pair of e⁻ to form the coordinate bond

what are the different types of ligands

Monodentate ( 1)

Multidentate ( multiply)

Bidentate ( 2)

Examples of monodentate ligands

:NH₃

Cl⁻

:CN⁻

H2O:

monodentate ligand

species with 1 lone pairs that can form co-ordinate bonds 

Multidentate ligand

species with more then 1 lone pairs that can form co-ordinate bonds 

Bidentate ligand

species with 2 lone pairs that can form co-ordinate bonds 

example of a bidentate ligand ( (Cu(en)₂)²⁺ )

2 lone pairs on the Nitrogen so it can 2 coordinate bonds

what is the shape of the complex ions based on?

coordination number ( number of coordinate bonds formed with the central metal ion)

what is the shape of a complex ion with 6 coordinate bonds

Octahedral shape

what is the bond angle of a octahedral shape

90°C

what are aqueous metals

hexaaqua complexes

what does `en` stand for

ethane-1,2-diamine ligand

what is the shape of a complex ion with 4 coordinate bonds

Tetrahedral shape

what is the bond angle of a tetrahedral shape

109.5°C

What is the other shape a tetrahedral shape could have

Square planar

what is the bond angle of Square Planar shape

90°C

Bidentate ligand image 

monodentate image

how to test for transition metals 

Add NaOH (aq)

what colour is Cu²⁺ precipitates

blue precipitate 

what colour is Fe²⁺ precipitates

green precipitate

what colour is Fe³⁺ precipitates

Brown precipitate 

what colour is Mn²⁺ precipitates

buff precipitate

what colour is Cr³⁺ precipitates

green precipitate

ionic equation for the reaction between Fe²⁺ and NaOH 

Fe²⁺(aq) + 2OH⁻( aq) → Fe(OH)₂ (s)

stereoisomerism definition 

same structural formula, different arrangement in space 

what is a trans isomer in complex ions

Ligands are 180°C apart

what is a CIS isomer in complex ions

ligands are less then 180°C apart

CIS/ Trans isomers ( Image)

differences between cis and trans platin

CIS platin is a anti-cancer drug ( binds to DNA in cancer cell)

Trans platin is not a anti cancer drug

cis and trans isomerism in square planar molecules ( Image)

what type of complex ions have optical isomers

Octahedral complexes with bidentate ligands 

Non- Superimposable mirror image ( image)

Ligand substitution what do transition metals exist as

hexaaqua complex ions ( has 6 H₂O ligands attached )

what colour is the Cr³⁺ metal aqua ion 

green solution 

when can ligands be substituted without change to co-ordination / shape

when ligands are similar sized and similar charge

which ligands can be substituted without change to co-ordination / shape and why

NH₃, H₂O, OH⁻ and CN ⁻

all similar size

equation for [ Cr ( H₂O)₆ ]³⁺ + NH₃ ( Ligand substitution)

[ Cr ( H₂O)₆ ]³⁺ (aq) + 6NH₃ (aq) → 6H₂O + [ Cr (NH₃)₆ ]³⁺(aq)

what is the shape when H₂O → Cl⁻  ligands are substituted 

Octahedral → Tetrahedral 

which ligand is a different size to the others

Cl⁻

equation for [ Cu ( H₂O)₆ ]²⁺ + HCl ( Ligand substitution)

[Cu( H₂O)₆ ]²⁺(aq) + 4Cl⁻(aq) ⇌ [CuCl₄]²⁻ + (aq) 6 H₂O (l) 

what is the colour change from [ Cr ( H₂O)₆ ]³⁺ to [ Cr (NH₃)₆ ]³⁺

green→ purple

colour from [ Cu ( H₂O)₆ ]²⁺ to [CuCl₄]²⁻

blue → yellow- green 

when does partial substitution of NH₃ happen

when excess NH₃ is added ( Cu )

partial ligand substitution of [ Cu ( H₂O)₆ ]²⁺ and excess NH₃

[ Cu ( H₂O)₆ ]²⁺(aq) + 4NH₃(aq) → 4H₂O(l) + [ Cu ( NH₃)₄ ( H₂O)₂ ]²⁺( aq)

what is the only shape Ag/Pt can form

square planar

what is the only shape Cl₂ can form and why

tetrahedral

Cl₂ is too large

which transition metal always undergoes partial ligand substitution with NH₃

Copper ( Cu)

what is the reactant when forming a chlorine ligand 

HCl

what are the type of reactions complex ions undergo

precipitation reactions

ligand substitution

when do transition metals undergo precipitate reactions 

when reacted with NaOH or NH₃ (aq)

What is the colour of the precipitate in the reaction between NaOH/ NH₃(aq) and Cu?

Blue precipitate

What is the colour of the precipitate in the reaction between NaOH/ NH₃(aq) and Fe²⁺

Green precipitate

What is the colour of the precipitate in the reaction between NaOH/ NH₃(aq) and Fe³⁺

Brown precipitate

What is the colour of the precipitate in the reaction between NaOH/ NH₃(aq) and Mn²⁺

Buff precipitate

What is the colour of the precipitate in the reaction between NaOH/ NH₃(aq) and Cr³⁺

Dark green precipitate

What is the colour of the precipitate in the reaction between excess NH₃ and Cr³⁺

green precipate

What is the Ionic Equation between Fe³⁺ and NaOH/ NH₃ ( precipitation reaction)

Fe³⁺ (aq) + 3OH⁻ (aq) → Fe(OH)₃(s)

What is the Ionic Equation between Fe²⁺ and NaOH/ NH₃ (precipitation reaction)

Fe²⁺ (aq) + 2OH⁻ (aq) → Fe(OH)₂(s)

What is the Ionic Equation between Mn²⁺ and NaOH/ NH₃ (precipitation reaction)

Mn²⁺ (aq) + 2OH⁻(aq) → Mn(OH)₂(s)

What is the Ionic Equation between Cr³⁺ and NaOH/ NH₃ ( precipitation reaction)

Cr³⁺(aq) + 3OH⁻(aq) → Cr(OH)₃(s)

What is the colour of the precipitate in the reaction between excess NH₃ and Cu²⁺

Dark blue

what is the colour of the chromate ion (Cr₂O₇²⁻)

orange

what are the colour changes in the oxidation of Cr³⁺→CrO₄²⁻ →Cr₂O₇²⁻

Cr³⁺ (green)→CrO₄²⁻ ( yellow) →Cr₂O₇²⁻ ( orange)

what reagnant reduces Fe³⁺ 

KI

what reagant oxidises Fe²⁺

MnO₄⁻/H⁺

what reduces Cr₂O₇²⁻

Zn/H⁺

what reduces Cu

I⁻

Shape of a central ion with 2 mono-dente ligands

Linear

how does haemoglobin transport O₂ around body

O₂ lone pair forms a co-ordinate bond with Fe (II)

O₂ bonds reversibly (can be replaced with CO₂/H₂O)

what are elements in the periodic table determined by

increasing atomic number

what is a d block element

element with highest energy electron in d subshell

why is CO toxic ?

binds irreversibly to Fe ( II)

what happens to Aqueous ionic molecules during ligand substitution

dissociate into ions

cations are hexa aqua