15. Transition Metals Flashcards
When forming ions, what subshell loses electrons first?
4s before 3d
transition metal characterists of elements SC to Cu arise from what?
an incomplete d sub-shell in ions
What do these characterists include?
.complex formation
.formation of coloured ions
.variable oxidation state
.catalytic activity
Why is Zn not a transition metal?
. Zn can only form a +2 ion
. In this ion the Zn+2 has a complete d orbital and so does not meet the criteria of having an incomplete d orbital in one of its compounds
Why is Sc not a transition metal?
. Sc can only form a +3 ion
. In this ion the Sc+3 has an empty d orbital and so does not meet the criteria of having an incomplete d orbit in one of its ions
What is the trend in successive ionisation energies from the elements Sc to Zn? why?
. a gradual increase until all the 4s and 3d electrons have been removed
. then there is a big jump as electrons start to be removed from the inner core electrons
What is a complex?
a central metal ion surrounded by ligands
What is a ligand?
an atom, ion or molecule which can donate a lone electron pair
What is co-ordinate bonding?
when the shared pair of electrons in the covalent bond come from only one of the bonding atoms
What is a co-ordination number?
The number of co-ordinate bonds formed to a central metal ion (the number of ligands bonded to a transition metal ion)
What does it mean if the ligand is monodentate?
They can form one coordinate bond per ligand
What does it mean if the ligand is bidentate?
When the ligand has 2 atoms with lone pairs and can form 2 coordinate bonds per ligand
What does it mean if the ligand is multidentate? give an example.
. it can form many coordinate bonds per ligand
. EDTA -4 can form 6 coordinate bonds per ligand
Is Cl- a monodentate or bidentate or multidentate?
monodentate
Is NH2CH2CH2NH2 a monodentate or bidentate or multidentate?
bidentate
Is H2O a monodentate or bidentate or multidentate?
monodentate
Is NH3 a monodentate or bidentate or multidentate?
monodentate
Draw an EDTA 4- anion.
cant add a picture lol
How many donor sites does the EDT 4- anion have? what are they?
. 6 donor sites
. 4O and 2N
What is the coordination number of [Cr(NH2CH2CH2NH2)3]+3?
6
What type of ligands are in [Cr(NH2CH2CH2NH2)3]+3? What does it tell us?
. bidentate
. Each ligand bonds twice in the metal ion
What do colour changes of transition metal ions arise from changes in? (3 things)
- oxidation state
- co-ordination number
- ligand
