Transition Metals Flashcards
What causes the special properties of transition metals
The incomplete d-subshell
Define transition metal
A metal than can form 1 or more stable ions with a partially filled d-subshell
A d-orbital can fit how many elections
10
All the period 4 d-block elements are transition metals apart from which 2
Scandium
Zinc
Physical properties of transition metals
High density
High melting and boiling points
Their ionic radii are nearly all same
Chemical properties of transition metals
Can form complex ions
Form coloured complexes
Good catalysts
Can exist in variable oxidation states
What is a complex ion
Metal ion surrounded by ligands
What is a coordinate/dative covalent bond
A covalent bond in which both electrons in the shared pair come from one atom. In a complex they come from ligands
What is a ligand
An atom, ion or molecule that donates a pair of electrons to a central metal ion
What is the coordination number
The number of coordinate bonds that are formed with the central metal ion
What are the usual coordinate numbers
6 and 4
If ligands are small like h2O then 6 can fit around central metal ion
If ligands are large like Cl- then only 4 can fit around central metal ion
How do you work out the oxidation state of a metal
The total oxidation state - the sum of the oxidation states of the ligands
A ligand must have at least one….
Lone pair of electrons, or it won’t have anything to use to form a coordinate/dative covalent bond
Heterogeneous catalysts info
There are in different phase from the reactants for example in the Haber process gases are passed over solid iron catalyst. Reaction happens on surface of the heterogeneous catalyst. So increasing the surface area of the catalyst increases number of molecules that can react at the same time, increasing rate of reaction. Support mediums often used to make area of catalyst as large as possible. Eg catalytic converters contain ceramic lattice coated with thin layer of rhodium. Rhodium acts as catalyst helping convert gases to less harmful products. Lattice structure maximises surface area of catalyst making it more effective. It minimises cost of catalyst as only thin coating needed
Homogeneous catalysts info
In same physical state as reactants, usually aqueous catalyst for reaction between 2 aqueous solutions.
