M5 - Transition Elements Flashcards
A
What is a ligand?
A molecule or ion that can donate a pair of electrons to the transition metal ion to form a coordinate bond
What are transition elements?
D-block elements that form at least one ion with a partially filled d-orbital.
What is stereoisomerism?
Same structural formula but a different arrangement of the atoms in space.
What colour is hydrated copper(II) sulfate?
Blue
D
Which d-block elements are excluded from being transition elements?
Scandium and zinc. scandium forms a sc 3+ ion and zinc forms a Zn 2+ ion.
the zinc is empty and scandium is scant.
What is Coordination number?
The total number of coordinate bonds formed between a central metal ion and its ligands
C
What is a precipitation reaction?
a precipitation reaction is when two aqueous solutions contain ions react together to form an insoluble ionic solid. (the precipitate)
B
What is a Monodentate ligand?
A molecule or ion that can donate one pair of electrons to the transition metal ion to form one coordinate bond
Describe ligand substitution of aqueous copper(II) ions with chloride ions
six H2O ligands are replaced by 4 chloride ions Cl- ligands. The solution starts out pale blue and moves to yellow on completion.
[Cu(H2O)6]2+ + 4Cl- = [CuCl4]2- + 6H2O
What is optical isomerism?
Non-superimposable mirror images of each other.
Called enantiomers
Describe the reaction between [Cr(H2O)6]3+ and an excess of aqueous ammonia
A grey green precipitate of Cr(OH)3 is formed initially.
Cr(OH)3 dissolves in excess ammonia to form the complex ion [Cr(NH3)6]3+.
A purple solution.
B
Describe the precipitation reaction of Cr3+ with OH and what is the equation?
Cr3+ (aq) + 3OH- (aq) = Cr(OH)3 (s)
violet solution to green precipitate
Describe the precipitation reaction of Fe3+ with OH and what is the equation?
Fe3+ + 3OH- = Fe(OH)3 (s)
pale yellow to orange-brown precipitate
What colour is potassium dichromate(VI)?
K2Cr2O7 is Orange
What is a complex ion?
A transition metal ion bonded to one or more ligands by coordinate bond
What is a Transition Element? (1)
A d-block element that forms an ion with an incomplete d sub-shell (1)
What are the properties of the transition elements?
1) transition elements form compounds with different oxidation states.
2) Form coloured compounds
3) Elements and compounds can act as catalysts
Define ligand substitution
Ligand substitution is a reversible reaction of a complex ion where One ligand in a complex ion is replaced by another ligand.
What is a Bidentate ligand?
A molecule or ion that donates two lone pairs of electrons to the central metal ion to form two coordinate bonds
What is a Coordinate bond (dative covalent bond)?
Shared pair of electrons in which one of the bonded atoms provides both electrons for the shared pair
D
When can complex ions show cis-trans isomerism?
cis-trans isomers exist in square planar and octahedral complex ions.
Describe the precipitation reaction of Fe2+ with OH and what is the equation?
Fe2+ + 2OH (OH- ions) = Fe(OH)2 (s)
pale green solution to green precipitate
Describe the precipitation reaction of Mn2+ with OH and what is the equation?
Mn2+ + 2OH- = Mn (OH)2 (s)
pale pink solution to light brown precipitate
What shapes can be created from a complex ion having a coordination number of 4?
when there is a coordination number if 4 the shape is:
Tetrahedral
OR
Square planar
