1.3 transition metals Flashcards
how do homogeneous catalysts work?
by changing oxidation state, which allows the formation of intermediate complexes.
how do heterogeneous catalysts work?
they adsorb reactant molecules to their active sites, where the presence of unpaired d electrons allows an activated complex to form
what is a homogeneous catalyst?
a catalyst in the same state as the reactants
what is a heterogeneous catalyst?
a catalyst in a different state to the reactants
why may a complex be colourless?
the absorbed energy from the d-d transition is in the UV part of the spectrum rather than the visible
the TM has a full d subshell so there is no capacity for electrons to transfer
what makes the colours in TM metals?
if light from the visible spectrum is absorbed
when is light absorbed?
during d-d transition
what is the spectrochemical series, from largest to smallest split?
CN-, H20, OH-, F-, Cl-, Br-, I-
how is the ability of ligands to cause splitting given by?
the spectrochemical series
how is the loss of degeneracy referred to?
splitting of d orbitals
why is there a loss of degeneracy in a transition metal ion in a compound?
the ligands create an electrostatic field and repel electrons in some of the TM’s orbitals
in which type of transition metal ion are the 3d orbitals degenerate?
a free ion
why are simple and complex ions of transition metals often coloured?
because they absorb light in the visible spectrum
when writing the formula of a coordination compound, which order should ligands be written in?
alphabetical order by formulae
when writing the formula of a coordination compound, how should the formula of a ligand be written?
with the element connecting to the transition metal ion appearing first
in coordination compounds, what should the charges balance to?
0
when naming coordination compounds, where should the negative ion be written?
after the complex
when naming coordination compounds, where should the positive ion be written?
before the complex
when is a coordination compound formed?
when a complex ion combines with an oppositely charged ion
what are two examples where metals use their Latin name when converted to ‘ate’?
ferrate, cuprate
what is the name of water in a complex ion?
aqua
what is the name of carbon monoxide in a complex ion?
carbonyl
what is the name of ammonia in a complex ion?
ammine
what changes about negative ligand names when the complex ion is negative?
the e changes to an o
what changes about the transition metal name if the complex ion is negative?
it ends in ‘ate’
what must the metal part of the complex name be followed by?
its oxidation number written as roman numerals
which part of the complex is named first?
the ligand(s) in alphabetical order
what is the coordination number?
the number of bonds formed between the central metal ion and the surrounding ligands
what are the three common types of ligands?
monodentate, bidentate, hexadentate
how are ligands classified?
based on the number of electron pairs they donate/the number of bonds they form with the central ion
which type of bond do ligands form with the central metal ion?
dative
how do ligands bond to the metal?
they donate non-bonding electron pairs into unfilled metal orbitals
what are ligands?
a molecule or negative ion with one or more non-bonding pairs of electrons. they are electron donors
what does a complex consist of?
a central metal ion surrounded by ligands
ions in different oxidation states often show different…
colours
which compounds tend to be reducing agents?
compounds with metals in low oxidation states
which compounds tend to be good oxidising agents and why?
- compounds with metals in high oxidation states
- the ions are easily reduced to lower oxidation states
what is the sum of all of the oxidation numbers in a polyatomic ion?
equal to the charge
what is the sum of all of the oxidation numbers in a molecule?
0
what is always the oxidation number of fluorine?
-1
what is always the oxidation number of group 2 metals?
+2
what is always the oxidation number of group 1 metals?
+1
what is the oxidation number of a hydride ion?
-1
what is the oxidation number of hydrogen in most compounds?
+1
what is the oxidation number of oxygen in most compounds?
-2
what is the oxidation number of monatomic ions?
equal to the charge
what is oxidation number related to?
the number of electrons a species has lost or gained
what is the oxidation number of a free element?
0
what the typical transition meta properties?
forming coloured ions
forming complexes
having variable oxidation states
showing catalytic activity
which two metals do not have an incomplete d subshell in any of their ions, meaning that they don’t have typical transition metal properties?
scandium and zinc
transition metals have a __ valency, meaning…
variable, they can form ions of different charges by losing different numbers of electrons
what are some important uses of TMs?
piping and wiring, coins, construction, jewellery and catalysts
what is the definition of a TM?
metals with an incomplete d subshell in at least one of their ions
