Transition Metals Flashcards
What is a transition metal?
Transition metals are d block elements that can form at least one stable ion with an incomplete d sub-level.
What are variable oxidation states?
Transition metals can form a number of stable ions, each with the metal in a different oxidation state.
What is a ligand?
A ligand is any atom, ion or molecule which can donate a pair of electrons to a metal ion. Ligands are Lewis bases and nucleophiles.
How are ligands classified?
Ligands are classified by the number of dative covalent or coordinate bonds that they can make.
What is an example of a unidentate ligand?
Water molecules frequently act as ligands, making a single bond with the metal ion.
What is a multidentate ligand?
Multidentate ligands contain more than two atoms that donate pairs of electrons to form coordinate bonds.
What does EDTA 4– do?
EDTA 4– forms six coordinate bonds with a metal ion, forming chelates.
What are bidentate ligands?
Bidentate ligands contain two atoms that donate pairs of electrons to form coordinate bonds.
Fill in the blank: The coordination number is the number of _______ to the metal ion.
coordinate bonds
What is a complex?
A complex consists of a central metal ion surrounded by ligands forming coordinate bonds with the ion.
What is the coordination number for an octahedral complex?
6
What is cis-trans isomerism?
Cis–trans isomerism occurs because the ligands cannot rotate around the central metal ion.
True or False: Different stereoisomers can have different chemical properties.
True
What is optical isomerism?
Optical isomerism is when a molecule can exist as two forms that are non-superimposable mirror images of each other.
What happens when light is absorbed by transition metal complexes?
Electrons can be promoted to higher energy levels, requiring absorption of specific light frequencies.
What factors influence the color of transition metal ions?
- Coordination number
- Ligand type
- Oxidation state
What is the ground state in terms of electron energy levels?
The ground state is the lowest energy level (n=1).
What does E = hc represent?
E is the energy of the photon.
What is the formula for the relationship between frequency and wavelength?
v = c/λ
What is the significance of ultraviolet-visible spectroscopy?
It can be used to determine the concentration of substances.
When Fe2+ is in a complex what colour is it?
Green
What colour is Cu2+ when in a metal ion complex?
Blue
What colour is Fe3+ when in a metal ion complex?
Yellow
What colour is Al 3+ when in a metal ion complex?
Colourless
What is Ligand Substitution?
Process where one ligand is replaced by another.
What happens when you decrease ligand number during ligand substitution?
Decrease in coordination number means increase in enthalpy change.
[M(H2O)6]2+(aq) + H2O(l)
M(H2O)5(OH)]+(aq) + H3O+(aq)
[M(H2O)6]²⁺ + 2OH⁻ →
[M(OH)2(H20)4] + 6H2O
Cu(OH)₂(s) + 4NH₃(aq) →
[Cu(NH₃)₄(H₂O)₂]²⁺(aq) + 2OH⁻(aq) (deep blue solution)
