Transition metals Flashcards
The d block transition metals are metals with…
an incomplete d subshell in at least one of their ions.
the filling of the d orbitals follows the…
Aufbau principle, with the exception of chromium and copper atoms.
the exceptions of chromium and copper is due to..
the especial ability associated with the d subshell being half-filled or completely filled
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
an element is said to be in a particular oxidation state when…
it has a specific oxidation number
the oxidation number can be determined by the following:
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 a oxidation number of -2
in most its compounds hydrogen has a 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 of the ion
a transition metal can have…
different oxidation states in its compounds
compounds of the same transition metal in different oxidation states…
may have different colours
oxidation can be defined as an….
increase in oxidation number
reduction can be considered as a…
decrease in oxidation number
changes in oxidation number of transition metal ions can be used to determine…
whether oxidation or reduction has occurred
compounds containing metals in low oxidation states are often…
reducing agents
compounds containing metals in high oxidation states are often…
oxidising agents
ligands may be…
negative ions or molecules with non bonding pairs of electrons that they donate to the central atom or ion, forming dative covalent bonds
ligands can be classified as…
monodentate, bidentate up to hexadentate.
the total number of bonds from the ligands to the central transition metal is known as the…
coordination number
weak field ligands cause a…
small energy difference
strong-field ligands cause a …
large energy difference
ligands can be placed in order of their…
ability to split d orbitals. this is called the petrochemical series.
light is absorbed when…
electrons in a lower energy d orbital are promoted to a d orbital of higher energy
if the light of one colour is absorbed then…
the complementary colour will be observed
transition metals and their compounds can act as…
catalysts
the presence of unpaired d electrons or unfilled d electrons is thought to…
allow intermediate complexes form
intermediate complexes can provide…
reaction pathways with lower activation energies compared to the uncatalysed reaction
what is important about oxidation states of transition metals for catalysts…
variability
