transition metals Flashcards
why do transition metals have highballing points
both 4s and 3d electrons delocalised
stronger metallic bond
define transition metal
an element that has one or more stable ions with incompletely filled d orbitals
what is a d block element
have their highest energy, last valence electron in a d orbital
electron configuration of copper
[Ar] 3d10 4s1
electron configuration of chromium
[Ar] 3d5 4s1
which electrons are lost first
4s
how can the maximum oxidation number of a transition metal be calculated
adding the number of unpaired 3d electrons to the total number of 4s electrons
what is a characteristic property of transition metals
ability to form ions with various oxidation states
what is a ligand
a species dative covalently bonded to a central metal ion
what is a coordination number
number of coordinate bonds from ligands to central metal ion
order of how to name a ligand
1 number of ligands
2 name of ligand
3 central metal ion
4 oxidation number of metal ion
one ligand
mono-
two ligands
di-
three ligands
tri-
four ligands
tetra-
five ligands
penta-
six ligands
hexa-
CN- ligand name
cyano
OH- ligand name
hydroxo
H2O ligand name
aqua
NH3 ligand name
ammine
CO ligand name
carbonyl
what do complexes with a net negative charge’s metal ions end in (name)
-ate
copper overall negative charge name
cuprate
ion overall negative charge name
ferrate
name [Cr(Cl2)(H2O)4]+
di chloro tetra aqua chromium (III) ion
why do complex ions form coloured compounds
- ligand binding causes d orbitals to split
- light of certain wavelengths absorbed
- promotes e- to a higher energy orbital
- difference in energy levels determines the frequency absorbed and hence the colour observed
- remaining wavelengths of light are transmitted
- seen as colour in the visible region
what does the extent of the d orbital splitting (and hence the colour of the complex) depend on (3)
- nature of the ligand
- oxidation state of transition metal ion
- co-ordination number
colour of V2+
violet
colour of V3+
green
colour of V4+
blue
colour of V5+
yellow
why does a solution of Zn2+ have no colour
[Ar] 3d10
full d sub shell
no unpaired d orbital e-
movement of e- between d orbitals not possible
what is deprotonation
reaction in which the base removes a proton from the water molecules
what is a ligand exchange reaction
where a stronger ligand replaces a weaker one
mono dentate ligand
forms one co-ordinate bond
eg CN-
polydentate ligand
can form several co-ordinate bonds
eg EDTA 4-
bidentate ligand
forms two co-ordinate bonds
eg ethandioate
iron (II) solution
pale green
[Fe(H20)6]2+
iron (II) solution + sodium hydroxide
green precipitate formed
insoluble with excess
red/brown on standing
iron (II) solution + sodium hydroxide equation
[Fe(H2O)6]2+(aq) + 2OH- (aq) –> [Fe(OH)2(H2O)4] (s) + 2H2O (l)
iron (II) solution + ammonia
green precipitate formed
insoluble with excess
red/brown on standing
iron (II) solution + ammonia equation
[Fe(H2O)6]2+ (aq) + 2NH3 (aq) –> [Fe(OH)2(H2O)4] (s) + 2NH4+ (aq)
iron (II) solution + aqueous sodium carbonate
produces..
[Fe(OH)2(H2O)4] (s)
green precipitate
iron (III) solution
yellow/brown
[Fe(H2O)6]3+
iron (III) solution + sodium hydroxide
red/brown precipitate
insoluble with excess
iron (III) solution + sodium hydroxide equation
[Fe(H2O)6]3+ (aq) + 3OH- (aq) –> Fe(OH)3(H2O)3 + 3H2O(l)
iron (III) solution + ammonia
red/brown precipitate
insoluble with excess
iron (III) solution + ammonia equation
[Fe(H2O)6]3+ (aq) + 3NH3 (aq) –> [Fe(OH)3(H2O)3] (s) + 3NH4+ (aq)
iron (III) solution + aqueous sodium carbonate produces…
[Fe(OH)3(H2O)3] (s)
red/brown precipitate
chromium (III) solution
green
[Cr(H2O)6]3+
chromium (III) solution + sodium hydroxide
green precipitate
soluble with excess - dark green solution
chromium (III) solution + sodium hydroxide equation
[Cr(H2O)6]3+ (aq) + 3OH (aq) –> [Cr(H2O)3(OH)3] (s) + 3H2O (l)
with excess –> [Cr(OH)6]3- (aq)
chromium (III) solution + ammonia equation
[Cr(H2O)6]3+ (aq) + 3NH3 (aq) –> [Cr(H2O)3(OH)3] (s) + 3H2O (l)
with excess –> [Cr(NH3)6]3+ (aq)
chromium (III) solution + ammonia
green precipitate
soluble with excess - purple solution
cobalt (II) solution
pink
[Co(H2O)6]2+
cobalt (II) solution + sodium hydroxide
blue precipitate
insoluble with excess
turns pink on standing
cobalt (II) solution + sodium hydroxide equation
[Co(H2O)6]2+ (aq) + 2OH- (aq) –> [Co(H2O)4(OH)2] (s) + 2H2O (l)
cobalt (II) solution + ammonia
blue precipitate
soluble with excess - brown solution
darkens on standing
cobalt (II) solution + ammonia equation
[Co(H2O)6]2+ (aq) + 2NH3 (aq) –> [Co(H2O)4(OH)2] (s) + 2NH4+ (aq)
with excess –> [Co(NH3)6]2+ (aq)
copper (II) solution
blue
[Cu(H2O)6]2+
copper (II) solution + sodium hydroxide
pale blue precipitate
insoluble with excess
copper (II) solution + sodium hydroxide equation
[Cu(H2O)6]2+ (aq) + 2OH- (aq) –> [Cu(H2O)4(OH)2] (s) + 2H2O (l)
copper (II) solution + ammonia
pale blue precipitate
soluble with excess - deep blue solution
copper (II) solution + ammonia equation
[Cu(H2O)6]2+ (aq) + 2NH3 (aq) –> [Cu(H2O)4(OH)2] (s) + 2NH4+ (aq)
with excess –> [Cu(H2O)2(NH3)4]2+ (aq)
what kind of reaction is metal ion solution with NaOH
deprotonation
what kind of reaction is metal ion solution with excess NaOH
deprotonation
what kind of reaction is metal ion solution with NH3
deprotonation
what kind of reaction is metal ion solution with excess NH3
ligand exchange
