2.Transition Metals Flashcards
why do you lose 4s electrons first when ionising?
as the orbitals get attracted by the +ve neuclues different amount,
3d gets pulled more, so 4s is in the higher energy state.
what is a transition element?
has at least one stable ion with a partially filled d subshell
what are co-ordinate bonds?
dative covelant bons in a transition metal.
Lone pair from one atom is shared witht he trasition metal to form a bond
what is a ligand?
a molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond.
what is a complex ion?
a transition metal ion bonded to one or more ligands by coordinate bonds
reaction between Hexaaqua iron(II) ion and OH-
and why it happens.
[Fe(H2O)6]2+(aq) +2OH-(aq) –> Fe(OH)2(s) + 6H2O(l)
As OH- has a strong attraction then water
What happens with NH3 ligand substitution?
first OH- will displace
then when NH3 conc is high enough it will displace as its lone pair is more avalable
what is a monodentate ligand?
has one point of attachment with the transition metal ion.
what is a bidentate ligand?
has two points of attraction with the ligand
types of isomerism in complex ions?
cis/trans
optical isomers
Kc =
the constant for ligand substitution ractions starting from water ligands
[products]/[reactants]
Kstab = STability constant =
the equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex ion formed when the same ion has undergone a ligand substitution reaction
[Final complex ion]/[Original ion][new ligand]n
what does stability constant tell you?
how stable the new ligand is in comparisson the the water ligand.
the larger the value the further to the right the equilibrim is and the more stable the complex is.
electron config for Cr
…….. 3d5 4s1
as the replusion in the s orbital means that its of ahigher energy level
electron config for Cu
……… 3d10 4s1
4 properties of transition metals
- many oxidation states
- makes good catalysts
- multi coloured ions
- complex ions
why do transition metals make good catalyst?
they hae variable oxidation states
easy to form intermediates
easily adsorb reactants
why are there ions coloured?
they can adsorb energy from light to promote d electrons
(d shell must be partially filled)
colour of Co2+ in solution
pink
colour of Cu2+ in solution
blue
colour of Fe3+ in solution
pale green
colour of Fe2+ in solution
yellow
why do transition metal ios form complex ions?
small, high charge density
strongly polarising, and attractive to lone pairs
what is coordination number?
the numbe of coordinate bonds formed between the metal ion and its ligands.
why do some ligands substitute with les sof them?
if they have a charge at somepoint the ion will no longer be attractive enough to get another ligand of the same charge
and they might be bigger ligands so dont fit
why are two colour changes seen in some ligand substitutions?
as both colours are present so they mix
name for the water, ammonia, chlride ion and CN- ion ligands?
- water : aqua
- NH3 : ammine
- Cl- : chloro
- CN- : cyano
[Cu(H2O)6]2+ colour
Blue
[CuCl4]2- colour
Yellow
[Cu(NH3)4(H2O)2]2+colour
Dark blue
[Fe(H2O)6]2+ colour
pale green
[Fe(H2O)6]3+ colour
yellow
[Fe(H2O)5SCN]2+ colour
blood red
Cu(OH)2 colour
pale blue preceip
Fe(OH)2 colour
green (goes brown in air) precip
Fe(OH)3 colour
brown precip
what is a d block element?
highest energy electron in the d block (in a d-subshell)
colour of Co(OH)2
blue (beige in air) precip
requirement for optical isomer of a complex ion?
- 3 bidentate ligands
- 2 bidentate 2 mono dnetate
- one hexadentate
colour of [CoCl4]
blue
