Transition Metals Flashcards
What is a transition metal? What conditions to be classed as one?
Transitions metal is an element in the d-block element of the p.t that forms at least one stable ion with an partially filled d sub-shell
1) Electrons must be in d sub shell, and highest energy outermost electron in a d sub-shell
2) incomplete d sub-shell
How does the electronic configuration of d block ions work?
When they lose electrons, they lose electrons from the 4s orbital first and then the 3d orbital ( and vice verse ).
Give the pattern of electrons in the d sub shell for the top row of d block
1 2 3 5 5 6 7 8 10 10
Why is [Ar] used when describing electronic configuration
Noble gas that describes the electronic configuration ( in previous row )
What are the 4 main properties of transition metals?
1) variable oxidation states
2) form complex ions
3) form coloured compounds/ ions
4) act as catalysts
Why does Fe has a variable oxidation states?
2+ and 3+ ions
4s and 3d energy levels are so close in energy, so electrons gained and lost have a similar amount of energy
What is a catalyst? Give examples of 3 heterogenous catalysts, and one homogenous catalyst
Increases the rate of reaction by providing alternative pathway with lower AE
3 examples of use of heterogenous catalyst :
Haber process ( iron catalyst ( s ) ) to form ammonia
Formation of sulfur trioxide from sulfur dioxide and oxygen ( vanadium oxide ( s ) )
Decomposition of hydrogen peroxide
Hydrogenation with nickel catalyst
1 example of homogenous catalyst :
Reaction between iodine ions and peroxodisulfate ions ( s2 o8 2- ) with fe 2+ ion catalyst ( all aqueous )
Decomposition of hydrogen peroxide ( manganese( II ) oxide )
Why are chromium and copper exceptions exceptions in terms of electrons?
An electron from the 4s orbital moves into the 3d orbital to create a more stable half full / full 3d sub-shell
What is a complex ion?
A complex ion is a transition metal surrounded by coordinately bonded ligands.
What is a ligand?
A molecule or ion that donates a lone pair of electrons to the central metal ion to form a dative covalent bond
What is the coordination number?
The number of coordinate bonds with the ligands and central transition metal.
What is a monodentate ligand? Give examples of this
The ligand donates one pair of electrons to form one dative covalent bond with a central metal ion.
Examples :
Water ( donates one pair of electron )
Ammonia
Chloride ions
Cyanide ions
What is a bidentate ligand? Give examples of this
Forms 2 covalent bonds wish the central transition metal
1) ethandioate ( C2O4 2- ) ( formed from a carboxylic acid ) ( 2 oxygen ions with a lone pair )
2) ethane-1,2-diamine ( 2 nitrogen ions with a lone pair )
What is a multidentate ligand? Give the main example
EDTA, EDTA 4-
Forms 6 coordinate bonds
4 O- and 2 N’s
What is the colour of Cu2+ ( aq)?
Blue
What is the colour of Cu(OH)2?
Blue precipitate
What is the colour of the Fe2+(aq )?
Pale green
What is the colour of Fe3+?
yellow
What is the colour of Mn2+?
Pale pink/light pink
What is the colour of Cr3+?
Violet in aqueous solution when surrounded by 6 H20 but can be green
Why are scandium and zinc not transition metals?
Scandium only has an Sc3+ ion. The electronic configuration of this is …. . Scandium has an empty d sub shell. This is not partially filled, so it is therefore not a transition metal. Zinc only has a stable Zn2+ ion. The electronic configuration of this is ….. this is not partially filled so it is not a transition metal. They both do not meet the criteria ( mention definition )
What is the colour of V2+, V3+, and VO 2+?( vanadium )
V 2+ = violet
V 3+ = green
VO 2+ = blue
What is the colour of vanadium dioxide? ( VO2 + )
Yellow
What is the colour of Mn2+?
Pale pink
How are transition metals good for catalysis? What is the risks of catalysts?
Surfaces that allow substances to adsorb which lowers the AE of a reaction
Copper = chronic ( long term ) exposure can cause damage to liver - ring of copper in eye shows copper poisoning
Manganese = psychiatric issues and physical tremors
What are the 3 types of complex shapes?
1) Octahedral shapes
- coordination number 6
- 90 degree bond angles
2) Tetrahedral
- coordination number 4
- 109.5 degrees
3) square planar ( silver )
- coordination number 4
- 90 degree
Specific example of anti cancer drug cis-platin
How do you calculate the total oxidation state of the metal?
Total oxidation state - total oxidation state of ligand
