Transition Metals Flashcards
Unit 1
five properties of transition metals:
*have atoms/ions with an incomplete d-subshell
*can form complexes
*have variable oxidation states
*show catalytic ability
*form coloured ions
what is the definition of a transition metal?
a metal that, in at least one of its stable ions, has a partially filled d-subshell
what is the oxidation number of a free, uncombined atom?
0
what is the oxidation number of an ion of a single atom?
the same as its charge
in it’s compounds, Fluorine always has the same oxidation number. What is it?
-1
what must the algebraic sum of the oxidation number always be equal to?
0 or the charge of the ion
what is happening when there is an increase in the oxidation number?
oxidation
what is happening when there is a decrease in the oxidation number?
reduction
what do compounds containing metals in high oxidation states tend to be?
oxidising agents
what do compounds containing metals in low oxidation states tend to be?
reducing agents
what are two examples of oxidising agents?
acidified permanganate and acidified dichromate
what can be observed as oxidation state changes?
colour change
what other term can be used to refer to metal complexes?
co-ordination compounds
what are the molecules or ions which surround central metal atom/ion called?
ligands
what do ligands contain in order to form a co-ordinate bond?
(at least one) lone pair of electrons
what type of bond is a co-ordinate bond?
a dative covalent bond
how is the dative covalent bond formed?
the ligand donates the lone pair of electrons into an empty orbital in the transition metal atom/ion.
what is meant by a monodentate ligand?
ligands that form one co-ordinate bond to the metal atom/ion.
what is meant by a bidentate ligand?
ligands that form two co-ordinate bonds to the metal atom/ion.
what type of ligands bind in haemoglobin?
quadridentate ligands
what is an example of a hexadentate ligand?
EDTA
what is meant by the co-ordination number?
the total number of co-ordinate bonds from the ligand to the central metal atom/ion.
why are ligands referred to as Lewis bases?
they donate electrons
why are the metals, in turn, referred as Lewis acids?
they accept the electrons
what is a homogenous catalyst?
a catalyst that is in the same state as the reactants
what is a heterogenous catalyst?
a catalyst that is in a different state to the reactants
