TRANSITION METALS
The d block transition metals are metals with an incomplete d subshell in at least
one of their ions
This results in the following properties
Hard with high mpbp
show more than one oxidation state
Form coloured complexes
show catalytic activity
The filling of the d orbitals follows the Aufbau principle with the exeption of
chromium and copper atoms
These exceptions are due to the special
stability associated with the d subshell
being halffilled or completely filled
Scandium: Only forms Sc3+ ion
Zinc: Only forms Zn2+
leaving the 3d completely full.
Therefore Scandium and Zinc are not considered
as true transition metals.
When atoms from the first row of the
transition metals form ions it is the 4S
electrons that are lost first rather than
the 3d electrons
, OXIDA ON STATES
An element is said to be in a particular oxidation state when it has a specific
oxidation number
Oxidation Is the Loss of electrons.
Since transition metals can form more than one ion and are also present in complex ions, such as
MnO4-, it is useful to be able to di erentiate these in redox reactions.
The transition metals can be in di erent oxidation states.
The Oxidation Number (this relates to the oxidation state) can be worked out by following certain rules:
• Uncombined elements have an oxidation number of 0
• Ions containing single atoms (monatomic atoms) have an oxidation number that is the same as the
charge on the ion. [Note that the charge is written 2+ (two positive) whereas the Oxidation Number is
written +2 (positive two).]
• In most of its compounds, oxygen has the 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 0
• The sum of all the oxidation numbers of all the atoms in a polyatomic ion must be equal to the overall
charge on the ion
worked examples
fi
The d block transition metals are metals with an incomplete d subshell in at least
one of their ions
This results in the following properties
Hard with high mpbp
show more than one oxidation state
Form coloured complexes
show catalytic activity
The filling of the d orbitals follows the Aufbau principle with the exeption of
chromium and copper atoms
These exceptions are due to the special
stability associated with the d subshell
being halffilled or completely filled
Scandium: Only forms Sc3+ ion
Zinc: Only forms Zn2+
leaving the 3d completely full.
Therefore Scandium and Zinc are not considered
as true transition metals.
When atoms from the first row of the
transition metals form ions it is the 4S
electrons that are lost first rather than
the 3d electrons
, OXIDA ON STATES
An element is said to be in a particular oxidation state when it has a specific
oxidation number
Oxidation Is the Loss of electrons.
Since transition metals can form more than one ion and are also present in complex ions, such as
MnO4-, it is useful to be able to di erentiate these in redox reactions.
The transition metals can be in di erent oxidation states.
The Oxidation Number (this relates to the oxidation state) can be worked out by following certain rules:
• Uncombined elements have an oxidation number of 0
• Ions containing single atoms (monatomic atoms) have an oxidation number that is the same as the
charge on the ion. [Note that the charge is written 2+ (two positive) whereas the Oxidation Number is
written +2 (positive two).]
• In most of its compounds, oxygen has the 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 0
• The sum of all the oxidation numbers of all the atoms in a polyatomic ion must be equal to the overall
charge on the ion
worked examples
fi
