Unit 2: Section 4- Transition Metals (2.5) Flashcards
What are the four main characteristics of transition metals?
- complex formation
- formation of coloured ions
- variable oxidation state
- catalytic activity
Define transition metal
elements that can form one or more stable ions with a partially filled d sub-level.
What metal is not classed as a transition metal?
it can only form the Zn2+ ion, which has a full d sub-level. As the Zn2+ ion has a full d sub-level, zinc is not classed as a transition metal.
Define complex
a central metal ion surrounded by ligands.
Define ligand
An atom, ion or molecule which can donate a lone electron pair
When is a coordinate/dative bond formed?
when the shared pair of electrons in a covalent bond comes from just one of the bonded atoms.
What is the coordination number?
tells us the number of coordinate bonds to the central metal atom or ion.
What three things can ligands be?
monodentate- can form one bond per ligand
bidentate- can form two bonds per ligand
multidentate- more
What is a monodentate ligand?
only one atom donates an electron pair, so one coordinate bond is formed per ligand
What is an example of a monodentate ligand? (4)
NH3
Cl-
CN-
H2O
What would be the change in coordination number if H2O is replaced with NH3?
no change in coordination number, because they are the same size
Give an example of an element that goes through incomplete substitution with monodentate ligands
Cu
What type of reaction can happen when chloride ions are added to aqueous complex ions?
ligand substitution reaction
What is different about Cl- from H2O and NH3?
Cl- is bigger, so there is a change in coordination number in a ligand substitution reaction
What colour is this [CuCl4]2- ?
yellow/green solution
