Transition Metals Flashcards by alina gatley

What is a TM

An element with a partly filled d or f subshell

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What are the types of d orbitals

T2g dxy dxz dyz

Eg dz2 dx2-dy2

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Why do TM cations have no 4e-

Lower energy than d

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What are the exceptions in the elements

Copper and chromium

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What is the trend in IE

Increase in general but dip at d5 due to pairing

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What has the most oxidation states

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What is oxidation group state

Loss of all valence electrons - can be achieved by those on the LHS

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What is a metal complex

A combination of a Lewis acid ( metal ) and Lewis base (ligand)

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What is coordination number

Number of ligand donor atoms bonded directly to the metal

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What factors effect CN

Size of central atom
Steric interactions
Electronic interactions

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What did Werner discover

That CoCl3 NH3 4

Was in the octahedral geometry inorder to produce 2 isomers with different colours

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What are the isomers for MX4Y2

Cis and trans

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What are the isomers for MX3Y3

Mer and fac

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What property causes he rotation of polarised light

Chirality

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What properties do enatiomers have that are different

Reactivity with polarised light and reactivity with other chiral compounds

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How can you separate enantiomers

React with a chiral reagent such as d tartrate

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What shape do CN 6

Octahedral

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What is the distortion of octahedral

4 fold rotation tetragonal

3 fold rotation trigonal

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Why don’t CN greater than 6 occur

The atom is too small

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What shape are CN2

Linear

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What shape are CN4

Terreahedral or square planar

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What shape are CN 5

Trigonal bipyramidal or square pyramidal

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What exchange occurs in CN 5

Berry Pseudorotation - Luganda exchange between sites (fluxional )

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What does a hard coordination centre mean

Little affected by applied magnetic field

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What does soft centre mean

Easily polarised

What sort of bond is formed from hard hard

Pure ionic

What factors effect hard or soft centres

Atomic radii and electronegativity

What is a class a metal

A metal which forms its most stable complexes with hard oxygen donors

What is a soft metal

A metal which forms its most stable complexes with soft phosphorus donors

What assumptions does crystal filed theory make

That Ligands and metal ions are point charges | The bond is purely ionic

What is crystal field theory

That electrons in different d orbitals interact with ligands to different extents causing splitting in orbital energies

In the octahedral complex what is the order of orbitals

Eg T2g

Why do T2g lie lower in energy

They point inbtweeen ligands so repulsions are less

What is a spherical environment

When the transition metal ion is free

What is crystal field stabilisation energy

The occupation of electrons in the lowest level orbitals creating stabilisation

What is the value for delta o for T2g and eg

T2g -0.4 Eg +0.6

What is the equation for CFSE

= n(-0.4) +m (0.6) +xP

What is a low spin complex

When electrons occupy the lower levels pairing up before the higher

What is high spin

When orbitals enter higher levels avoiding pairing

What is a strong field case

A lower energy is achieved by occupying only the lower orbitals despite pairing

What is a weak field case

A lower energy is achieved by the upper orbitals being occupied

What is the Jahn Teller theorem

If the electrons are unequally distributed in the orbitals the complex distorts so the orbitals no longer have the same energy

Where is the Jahn Teller theory significant

Unequally occupied Eg orbitals

What is tetragonal distortion

The effect of Jahn Teller where z orbitals move down and the others move up to maintain average energy

What stabilisation occurs in square planar complexes

Complete removal of z axis z go v low

What are square planar complexes common on

When is square planar favoured over tetragonal distortion

When the delta exceeded pairing

What order are the orbitals in tetrahedral complexes

Opposite to octahedral

What is the equation relating delta t and delta o

T = 4/9 o

What is the consequence of the delta t delta o equation

Most tetrahedral complexes are high spin

Why do complexes have colour

They absorb light at a specific wave length and the wave length not absorbed is transmitted and observed

What equation links wave length and delta o

Wavelength = hc/deltao

What is the beer lambert law

A=ecl | A = log i0/I

What is 1cm-1 in Kjmol-1

0.012

How does ligand effect delta o

A large delta o is related to a strong field ligand

What does strong field ligand mean

The energy gap is large

How does the nature of the metal ion effect splitting

A large high oxidation state leads to larger splitting g

What 3 factors effect colour observed

Ligand type Metal type Geometry and co ord number

What is colour intensity governed by

Selection rules

What is the Laporte selection rule

L must be -+1

What is parity selection rule

The symmetry must change

What type of orbital has a centre of symmetry

G | S and d

What is the name of an orbital without a centre of symmetry

U | P

What is the spin selection rule

The chance of the electron changingspin is very low

What is a charge transfer

When the electron in a ligand temporary moves onto the metal ion or viscera

What causes the charge transfer to move to lower energy

Metal more oxidising | Ligand more reducing

What impact does a higher oxidation state have on energy level

Moves lower

What is paramagnetism

When there is an unpaired electrons

What is the opposite to paramagnetic

Diamagnetic

What is the spin only equation

U EFF = root n(n+2)

What is the practical consequences of paramagnetism in presence of magnetic field

Weight increases

What apparatus is used to weigh maganetic substances

gouy balance

What is ferromagnatism

Bellow a critical temp a paramagnetic ion remains aligned spontaneously

What does liable mean

The bond is easily broken / undergo rapid =bum

What does inert mean

The bond is stronger

What are the 2 mechanisms for ligand exchange

Sn1 or sn2

What factors effect rate or exchange

Oxidation state of metal | Distribution of 3D electrons

What is the formation constant equation

Kn= (MLn)/(MLn-1)(L)

What is the overall formation constant

K1 k2x....

What effects the trend in K

Statistics Sterics Electrostatics

What entropic effects k

Chelate effect | Changes in solvation

What is the chelate effect

Complexes with chelating multidentate rings are more stable than equivalent mono dentate due to effective conc and entropy

Transition Metals Flashcards

(82 cards)