Unit 1 Inorganic Chemistry: Key Area 3 - Transition Metals Flashcards
What is the definition of a transition metal?
Elements that have an incomplete d sub-shell in at least one of their ions.
What principle does the filling of the d orbitals follow in transition metals?
The filling of the d orbitals follows the aufbau principle.
What is the exception of the filling of d orbitals by the Aufbau principle?
Copper and Chromium which are due to the special stability associated with the d subshell being half- filled or completely filled.
What elements do not fit the definition for transition metals and why is this?
Scandium and zinc as they do not show metal ion characteristics and therefore do not exhibit colour.
What is oxidation?
A loss of electrons, gain of oxygen or an increase in oxidation number.
What is reduction?
A gain of electrons, loss of oxygen or decrease in oxidation number.
What is the rule for checking if oxidation has occurred?
Eat Only Hot Curries:
- Electrons
- Oxygen
- Hydrogen
- Charge
When atoms from the first row of the transition elements form ions, what are lost first.
When atoms from the first row of the transition elements form ions, it is the 4s electrons that are lost first rather than the 3d electrons.
When is an element said to be in a particular oxidation state?
An element is said to be in a particular oxidation state when it has a specific oxidation number.
How can the oxidation number be determined?
- Uncombined elements have an oxidation number of 0.
- Ions containing single atoms have an oxidation number that is the same as the charge on the ion.
- In most of its compounds, oxygen has an oxidation number of -2.
- In most of its compounds, hydrogen has an oxidation number of +1.
- The sum of all the oxidation numbers of all the atoms in a molecule or neutral ion must add up to zero.
- The sum of all the oxidation numbers of all the atoms in a polyatomic ion must be equal to the charge on the ion.
What do transition metals have in terms of stability?
Transition metals have variable oxidation states in terms of differing stability.
What is the charge on a cyanide (CN) ion?
-1
What can compounds of the same transition metals in different oxidation states have?
Different colours
Compounds containing metals in high oxidation states are often what?
Oxidising agents
Compounds containing metals in low oxidation states are often what?
Reducing agents
What do transition metal complexes consist of?
A central transition metal ion surrounded by ligands.
What are ligands?
Ligands may be negative ions or molecules with non-bonding pairs of electrons that they donate to the central metal atom or ion, forming dative covalent bonds.
What can ligands be classified as?
Ligands can be classified as monodentate, bidentate, up to hexadentate.
What are the key features of a monodentate ligand?
- Can only form 1 bond with the central metal atom/ion.
- One binding site
- e.g. ammonia and chlorine.
What are the key features of a bidentate ligand?
- Can form 2 bonds with the central metal atom/ion.
- Two binding sites.
- e.g. diaminoethane and oxalate ion.
- WILL ALWAYS USE BOTH BINDING SITES.
What are the key features of a tridentate ligand?
- Can form 3 bonds with the central metal atom/ion.
- Three binding sites.
- e.g. 1,4,7-triazaheptane.
- WILL ALWAYS USE ALL THEEE BINDING SITES.
What are the key features of a hexodentate ligand?
- Can form 6 bonds with the central metal atom/ion.
- Six binding sites.
- e.g. Chlorophyll and haemoglobin.
- WILL ALWAYS USE ALL SIX BINDING SITES.
What is a coordination number?
The number of lone pairs bonded to the central metal ion.