5.3.2 Transition metals Flashcards
what block are Sc to Zn in?
d block
which are transition elements?
Ti to Cu
what are transition elements
d-block elements which form at least one ion with a partially filled d orbital
properties of transition metals
compounds have different oxidation states
they form different coloured compounds
the elements and they’re compounds can act as catalysts
what colour is Fe(II)
pale green
what colour is Fe(III)
yellow
what colour is Cr(II)
blue
what colour is Cr(III)
green
what colour is Cr(VI)
orange/yellow
examples of transition metals as catalysts
(4 examples)
iron in harber process
Ni in hydrogenation
vanadium oxide in contact process
magenese oxide in decomposition of hydrogen peroxide
complex ions definition
when transition metals are in solution
what is the metal ion surrounded by in complex ions
ligands
what is a ligand
molecule or ion that forms a co-ordinate bond(dative covalent) by donating a pair of electrons to the central metal ion
what are co-ordination numbers
total number of coordination bonds which a metal ion forms
cyanide ion
CN-
what colour precipitate forms when NaOH or NH3 added dropwise to Mn2+
light brown ppt
what is colour of Mn2+
pale pink
bond shape and angle does 6 coordinate complex have
octahedral, 90 degrees
example of monodenate ligand
H2O, NH3, Cl-, CN-, OH-
what does a BIDENTATE ligand do
forms 2 coordinate bonds to metal ion
when filling electrons in an atom, is 4s or 3d filled first
4s
colour change observed when adding excess NaOH to Cr3+
violet solution to dark green solution
how can Cu2+ be reduced to Cu+
iodide ions
what colour precipitate forms when NaOH or NH3 added to Cr3+
green ppt
how can Cr3+ be oxidised to chromate(VI)
hot H2O2 with OH-
3 properties of transition elements
form multiple oxidation states
coloured compounds
elements and compounds can act as catalysts
how can Cu2+ be reduced to Cu+
iodide ions
colour of Fe2+
pale green
colour change when adding excess NaOH to Cr3+
violet to dark green
how can dichromate be reduced to Cr3+
zinc metal
what colour results when excess ammonia added to Cr3+
purple solution
what type of sterioisomer does the complex [Pt(NH3)2Cl2] show
cis- trans
colour result when ammonia added to Cr3+
grey-green ppt
colour ppt when NaOH or NH3 added to Fe3+
orange-brown ppt
why is CO toxic
CO forms stronger coordinate bond to Fe2+ in haem than O2 so bind irreversibly
why is it called d block
highest energy electrons are in d orbitals
what ligand substitution happens in haemoglobin close to a respiring cell
O2 lignand of oxyhaemoglobin is substituted by CO2 to make carboxyhaemoglobin
how can Cu+ be disproportionated to Cu and Cu2+
add dilute sulfuric acid
which 2 elements in first row of d block are not transition elements
Sc and Zn
how can Fe2+ be oxidised to Fe3+
maganate(VII), MnO4- with H+
definition of a transition element
d-block elements which form at least one ion with partially filled d orbital
colour change when excess ammonia added to Cu2+
dark blue solution
how can Fe3+ be reduced to Fe2+
iodide ions
colour of Cu2+
blue
type of sterioisomerism does complex [Pt(NH3)2Cl2] show
cis trans
colour of Fe2+
pale green
colour of ppt forms when NaOH or NH3 added dropwise to Mn2+
light-brown ppt
what does bidentate ligand do
forms 2 coordinate bonds to metal ion
what happens to haemoglobin as blood passes through lungs
haem group containing Fe2+ forms a coordinate bond to O2 molecule
colour change when HCl is added to Cu2+
pale blue solution to yellow
colour ppt when NaOH or NH3 added dropwise to Fe3+
orange-brown ppt
define ligand substitution reaction
1 ligand in a complex ion is replaced by another
type of isomer you can get with octahedral complexes with 2+ bidentate ligands
optical isomers
which have unusual electron configurations in d block
chromium and copper
why is CO toxic
as it forms much stronger coordinate bond to Fe2+ in haem than O2 so binds irreversibly
colour when ammonia added to Cr3+
grey-green ppt
colour ppt when NaOH or NH3 added to Cu2+
blue ppt
how does cis-platin work as chemotherapy drug
binds to DNA preventing cell division
colour ppt when NaOH or NH3 added to Cr3+
green ppt
colour of Fe3+
pale yellow
colour when excess ammonia added to Cr3+
purple solution
colour change when adding excess NaOH to Cr3+
violet to dark green solution
colour of Mn2+
pale pink
how can dichromate be reduced to Cr3+
zinc metal
how can Cr3+ be oxidised to chromate(VI)
Hot H2O2 with OH-
colour change when ammonia added to Cu2+
pale blue solution to pale blue ppt
colour of Cr3+
violet
