Transition Metals Flashcards
What are d block transition metals?
Metals with an incomplete d sub shell in at least one of their ion.
4s electrons are lost before 3d electrons during ionisation to positive ions.
filling d orbitals follow the Aufbau principle. ( with the exception to chromium and copper atoms
What is the oxidation number of all elements?
0
What is the oxidation number of monatomic ions?
it is equal to their charge
In most compounds, what is the oxidation number of H & O
Hydrogen = +1 (except hydrides where H is -1)
Oxygen = -2 (except peroxides where O is -1)
What must the sum of all the oxidation numbers in a molecule equal?
0
What must the sum of all the oxidation numbers in a polyatomic ion equal?
The charge on the ion
How are oxidation numbers written?
Sign first then number after
What has occurred if there is an increase in oxidation number?
Oxidation has occurred
What has occurred if there is a decrease in oxidation number?
Reduction has occurred
What compounds tend to be oxidising agents
Compounds containing metals with high oxidation numbers, these oxidising agents are reduced to a lower oxidation number.
What compounds tend to be reducing agents
Compounds containing metals with low oxidation numbers, agents are oxidised themselves to increase oxidation number
What is a common oxidation state in transition metals and why?
It is very common to have a oxidation state of +2 as the 4s^2 electrons are lost before 3d electrons.
What is a transition metal complex?
Compounds made of transition metal ions bonded covalently to ligands.
What is a ligand?
A ligand is a molecule or ion electron donor which bonds to the metal ion by the donation of one or more electron pairs to unfilled metal ion orbitals.
What is classification?
Ligands can be classified according to the number of atoms they use to bond to a transition metal ion.
What are the neutral ligands?
Ammonia ( NH3 )
Water ( H20 )
Is an NH4 ligand positive or negative?
Positive
What are the ligands you have to remember?
Halide ions ( group 7 ) are negative
Cyanide ion (CN) -1
Nitrite ion ( NO2- ) -1
Oxalate ion ( C2O4 ) is -2
NH4 +1
What is a monodentate ligand?
Ligands which donate 1 pair of electrons
What are bidentate ligands?
Ligands which donate 2 pairs of electrons ( the 2 pairs of electrons must be on different parts of the molecule, not thew same atom )
What is a polydentate ligand?
A ligand has more than one pair of electrons donated to the central metal ion.
What is the coordination number?
The number of bonds of the ligand(s) to the central ion is called the coordination number.
what is the coordination number of (Cu(h2o)6)2+ and why?
6
the central Cu2+ ion is surrounded by 6 water molecules.
these are hexandentate ligands
What are the steps involved in writing the formula Of complexes?
1) Formula of complex ions are written in square brackets
2)Metal symbol comes first
3) negative ligands come next
4)neutral ligands come next
5)overall change is written after square brackets
Are transition metals usually + or - ? and why?
+
because they give electrons
Are non metals usually + or - ? and why?
-
because they receive electrons
what are the prefixes used in each number of the ligands?
1 - mono (optional)
2-di
3-tri
4-tetra
5-penta
6-hexa
7-hepta
8-octa
if a complex has a negative charge, what does the metal end in when naming these complexes?
-ate
eg, cobalt becomes cobaltate
iron becomes ferrate
manganese becomes manganate
When writing complexes, how is the oxidation state of the metal written?
After the metal, in roman numerals in brackets
What is a dative covalent bond?
When both electrons in a covalent bond come from the same atom, a dative covalent bond is formed.
what is a transition metal?
A metal with an incomplete d sub shell in at least one of its ions.
what 2 elements break the aufbau principle and why?
Chromium and copper due to increased stability of having a fully or half filled sub shell.
what two elements are not technically transition metals and why?
Scadium and Zinc as they do not form ions with incomplete d sub shells.
