Chemistry: Transition Metals Part 1
This flashcard set explores the definition and classification of transition metals, highlighting why Scandium and Zinc are exceptions. It also outlines the key properties of transition metals—such as forming colored compounds and acting as catalysts—and explains how these arise from their incomplete d sub shells.
Transition metal
A metal that can form one or more stable ions with an incomplete d sub shell
Key Terms
Transition metal
A metal that can form one or more stable ions with an incomplete d sub shell
Why are Sc and Zn d block elements
Because their outer electron is in a (3)d sub shell
Why are Sc and Zn not transition metals
They don’t form a stable ion with in incomplete d sub shell
What are the four characteristic properties of transition metals
Form coloured compounds
Variable oxidation state
Catalysts
What do the characteristic properties of transition metals arise due to
Incomplete d sub shell
Complex ion
Central metal ion surrounded by ligands
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Transition metal | A metal that can form one or more stable ions with an incomplete d sub shell |
Why are Sc and Zn d block elements | Because their outer electron is in a (3)d sub shell |
Why are Sc and Zn not transition metals | They don’t form a stable ion with in incomplete d sub shell |
What are the four characteristic properties of transition metals | Form coloured compounds Variable oxidation state Catalysts Form complex ions |
What do the characteristic properties of transition metals arise due to | Incomplete d sub shell |
Complex ion | Central metal ion surrounded by ligands |
Ligands | A molecule/ion that forms a coordinate bond with a transition metal by donating a pair of electrons |
3 types of ligands | Monodentate, bidentate and multidentate |
Monodentate ligands | Molecules/ions that can donate one electron pair to the central mental ion to form one coordinate bond |
Bidentate ligands | Molecules/ions that can donate 2 electron pairs to the central metal ion to form 2 coordinate bonds |
Multidentate ligands | Molecules or ions that can donate more than 2 electron pairs to the central mental ion to form more than 2 coordinate bonds |
Coordination number | The number of coordinate bonds to the central metal atom/ion |
What is coordination number not necessarily the same as | The number of ligands |
When is coordination number the same as number of ligands | In monodentate ligands |
What are the two common shapes of complex ions | Octahedral and tetrahedral |
What 2 other shapes are also sometimes complex ions | Square planar and linear |
Why do complexes containing water and/or ammonia ligands usually have an octahedral shape | Because they usually have a coordination number of 6 |
Why do complexes containing chloride ligands usually have a tetrahedral shape | They usually have a coordination number of 4 |
Why do complexes of copper and silver usually have a linear shape | They usually have a coordination number of two |
What are ligand substitution reactions | Reaction where one ligand is replaced by another |
Why does the coordination number and shape not chance when a ligand substitution reaction occurs between NH3 And H2O | They are similar in size |
equation for aqueous cobalt salts reacting with excess ammonia (all 6 water ligands replaceed) | [Co(H2O)6]2+ +6NH3 >< [Co(nh3)6]2+ +6H2O |
colouur change when aqueous cobalt II salts react with excess ammonia | pink to pale brown |
equation for aqueous copper II salts reacting with excess ammonia (4 water ligands replaced) | [Cu(H2O)6]2+ + 4NH3 >< [Cu(H2O)2(NH3)4]2+ +4H2O |
colour change when aqueous copper II salts are reacted with excess ammonia | pale blue to dark blue |
coordination number and shape for aqueous copper II salts reacting with excess ammonia (4 water ligands replaced) | 6-6 | octabhedral- octahedral |
why do reactions involving chloride ligands involve a change in coordination number AND SHAPE | chloride ligand larger than NH3 and H2O |
equation aqueous cobalt II salts reacted with conc hcl (all 4 ligands replaced) | [Co(H2O)6]2+ + 4Cl- >< [CoCl4]2- + 6H2O |
COLOUR, COORD NUMBER AND SHAPE aqueous cobalt II salts reacted with conc hcl (all 4 ligands replaced) | colour: pink-blue |
haemoglobin: coordination number of iron II in haem unit | 4 |
haemoglobin: shape around iron II i haem unit | square planar |
haemoglobin: what does planar haem unit bound to and what does it bind to in body | complex protein called globin both water and oxygen can bind to iron II as ligands |
haemoglobin: what happens inthe lungs as a result of the concentration of oxygen being high | equilibrium shifts right and water ligands are substituted for oxygen molecules to form haemoglobin |
haemoglobin: which is the process of water/oxygen binding to haemoglobin reversed | when oxyhaemoglobin gets to where it is needed |
haemoglobin: what is the coordination number around iron in oxyhaemoglobin | 6 |
haemoglobin: what can haemoglobin substitute H2O ligands for when carbo monoxide is inhaled | Co |
haemoglobin: why is carbon monoxide considered toxic | bond between carbon monoxide and iron II is very strong and not readily revewrsed preventsw oxygen being bonded to haemoglobin |
why are enthalpy changes usually quite small in ligand substitution reactions | often little change in number and types of bond present |
What happens when reactions occur that substitute bidentate and multidentate ligands for monodentate ligands | Complex formed often very stable and reaction hard to reverse |
When is a reaction feasible in terms of energy | If free energy, delta G, is negative |
What does delta G equal | Delta H - T delta S |
Why is there a large increase in entropy of a reaction when there is an increase in moles | Disorder is increased |
Chelate effect | Multidentate and bidentate ligands replace monodentate ligands to form complexes |
Why are transition metal ions coloured | Because they have an incomplete d sub shell |
What do all the d orbitals in a transition metal atom have exactly the same | Energy |
Why do complex ions have some orbitals with more energy than other | Interactions between ligands and electrons in d orbitals gives some more energy than others |
What does how the orbitals split depend on | The coordination number of the complex |
What are electrons promoted from and to when visible light is absorbed | Electrons promoted from lower energy (ground state) to higher energy (excited state) |
When transition metal ions absorb visible light corresponding to a colour this colour is… | Missing from the spectrum |
Why is the complementary colour to the one hat is absorbed seen | The remaining colours are transmitted |
What does the frequency of light absorbed depend on | The size of the energy gap |
Delta E equals | hv |
What is h | Plancks constant = 6.63x10-34 Js |
V equals (definition ) | Frequency of light absorbed |
V equals | c/ŷ |
C equals | Speed of light = 3x10^8 |
Ŷ equals | Wavelength of light |
what factors induce change of colour in reaction |
|
why does change in coordination number induce colour change | splitting in the dorbitals is different in octahedral complexes than tetrahedral so when coordination number changes from 6 to 4 colour will also change |
example colour change due to change in coordination number equation | [Co(H2O)6]2+ + 4Cl- >< [CoCl4]2- + 6H2O |
colour change [Co(H2O)6]2+ to [CoCl4]2- | pink to blue |
what is a change in coordination number always accompanied by | a change in ligand |
why does a change in ligand induce a colour change | different ligands have different effects on the energies of d orbitals so when ligand changes the size of deltaE changes and hence the colour changes |
example nickel ligand changing from H2O to NH3 | [Ni(H2O)6]2+ + 6NH3 >< [Ni(NH3)6]2+ + 6H2O |
colour change when nickel ligand changes from water to ammonia | green to blue |
why does a change in oxidation state induce a colour change | as oxidation state of metal increases so does size of energy gap, delta E. this leads to a change in colour |
example of irons ox state changing 2+ to 3+ | [Fe(H2O)6]2+ > [Fe(H2O)6]3+ |
what is spectrometry the study of | how electromagnetic radiation interacts with matter |
what is colorimetry a type of | spectroscopy |
what does a colorimeter measure and what does it give a measure of | measures amount of light absorbed by a solution and gives a measure of colour intensity |
what you must first do to find the concentration of an unknown | generate a calibration curve |
colourimetry experiment |
|
why must 4/5 standard solutions be made in colorimetry | to provide enough data to draw a line of best fit with confidence |
why must a filter be used in colorimetry | to select out the complementary colour, this is the light the sample absorbs |
stereoisomerism | compounds with the same structural formula but a different arrangement of atoms in space |
what type of complexes can exhibit stereoisomerism | square planar and octahedral |
when can cis-trans isomers form in square planar complexes | when it has 2 different ligands |
formula of cisplatin | [Pt(NH3)2Cl2] |
when can octahedral complexes exhibit cis-trans isomerism | 2 different ligands- 4 of one and 2 of another |
which complexes can exhibit optical isomers | octahedral complexes containing bidentate ligands |
optical isomers | non superimposable mirror images |
Examples of complexes that exhibit optical isomerism | [Ni(en)3]2+ and [Co(C2O4)3]3- |