module 5: murphy, transition metals Flashcards
what is a transition metal
a metal that forms at least 1 ion that has a partly filled d sub-shell
from Ti to Cu
not Sc or Zn
what are some properties of transition metals
- Variable oxidation states
- Form complex ions
- Form coloured compounds
- Behave as catalysts
- high density, melting point and boiling point
- good electrical conductors
give examples of transition metals as catalysts
iron - haber process
nickel - hydrogenation of C=C
vanadium pentoxide - contact process
what is a complex ion
a complex ion has ligands bonded to a central positive ion through dative covalent bonds
what is a ligand
an ion or a molecule that can form dative covalent bonds to a positive transition metal ion by donating an electron pair
so, they have a negative charge/lone pair of electrons capable of being donated, bc a ligand is a nucleophile
what is a monodentate ligand, with examples
a ligand that can form only 1 dative bond to the central metal ion
eg. H2O, NH3, Cl-
what is a bidentate ligand, with examples
a ligand that can form 2 dative bonds to the central metal ion, because each ligand has 2 atoms with a lone pair of electrons each
eg. 1,2-diaminoethane (NH2CH2CH2NH2)
what is a six-coordinate complex
an octahedral complex, formed when a central metal atom/ion forms 6 coordinate bonds
could be 6 with mono dentate ligands or 3 with bidentate ligands
what is a four-coordinate complex and what ligands can they be found with
when four coordinate bonds form with the central metal ion/atom, usually tetrahedral, sometimes square planar
tetrahedral - most common with 4 chloride ions as they are large, allowing only 4 to fit
square planar - most common with cyanide ions, found in cisplatin
can transition element complexes exhibit stereoisomerism?
yes, square-planar and octahedral complexes with two ligand pairs exhibit cis-trans isomerism
this is geometric isomerism
can transition metal complexes exhibit optical isomerism and what is it
octahedral complexes with bidentate ligands have optical isomers
the two forms are non-superimposable images of each other, they have no plane of symmetry and one image can’t be placed directly on the other
what is cis-platin
a cancer treatment drug
it passes through the cell membrane and undergoes ligand exchange, binding to nitrogen atoms on the bases in DNA
this distorts the DNA’s shape and prevents its replication
adverse effects:
- binds to healthy and cancerous cells, so other cells that replicate quickly eg. hair follicles are also affected
what is assumed when a transition element ion is in solution
assumed that it exists as a hexaaqua complex ion (i.e. it has six water ligands attached to it)
what is the ionic equation and colour change when NaOH or aqueous ammonia is added dropwise to Cu(II) in solution
what is the ionic equation and colour change when excess concentrated ammonia is added to the product
- partial ligand substitution of 2 water ligands by 2 hydroxide ligands
- another partial ligand subsitution
what is the ionic equation and colour change when NaOH or aqueous ammonia is added dropwise to Fe(II) in solution
what is the ionic equation and colour change when excess conc. ammonia is added to the product
no change with excess conc.
dark green ppt not pale green
what is the ionic equation and colour change when NaOH or aqueous ammonia is added dropwise to Fe(III) in solution
what is the ionic equation and colour change when excess conc. ammonia is added to the product
no change with excess conc
what is the ionic equation and colour change when NaOH or aqueous ammonia is added dropwise to Cr(III) in solution
what is the ionic equation and colour change when excess NaOH/aqueous ammonia is added to the product
with excess OH: green solution [Cr(OH)6]^3-
with excess NH3: purple solution [Cr(NH3)6]3+
what is the ionic equation and colour change when NaOH or aqueous ammonia is added dropwise to Mn(II) in solution
what is the ionic equation and colour change when excess concentrated ammonia is added to the product
no change with conc ammonia
what charge is found on a ligand
it depends on the charge if the metal, the ligands charge can be shown using. square brackets
does copper 2+ react with excess NaOH or excess conc ammonia
conc ammonia only
outline the structure and functions of haemoglobin
it a complex iron using Fe2+ and oxygen atoms form dative covalent bonds with Fe(II) to allow it to be transported in the blood and around the body
BUT oxygen molecules aren’t great ligands and are weakly bonded, letting them easily break off and be transported into cells
CO is toxic because its a better ligand than O and binds to Fe(II) strongly and irreversibly
what is the colour and formula when excess HCl is added to Cu2+
what is the colour and formula of Cu2+ when reacted with I-
what is the colour and formula when CoCl2.6H2O and water reacts with excess HCl
what is the colour of Cr in solution
what is the colour of chromium when excess NH3 is added
what is the colour and formula of Cr with excess OH- added
what is the colour and formula when Cr3+ is oxidised with hot alkaline H2O2
what is the formula and colour of the complex formed from FeCl3.6H2O
when it’s in water i thinkkkk
what is the colour change from MnO4^- to Mn2+
what is the colour change from I-/Fe3+ to I2/Fe2+
what is a coordination number
the number of coordinate bonds the central ion in a complex has
how do you draw 3D structures of optical isomers
LITERAL mirror image
like the bonds and EVEYRHING!!!!!
what’s happens to Cu+ in aqueous conditions
it readily disproportionates to Cu2+ and Cu
what transition complex is a pale blue solution
what transition complex is a pale blue precipitate
what transition complex is a dark blue solution
what transition complex is a yellow solution
what transition complex is a green solution
what transition complex is a purple solution
what transition complex is an orange solution
what transition metal complex is a pale pink solution
what transition complex is a pale brown precipitate
what transition complex is a pale green solution
what transition complex is a dark green precipitate
what transition complex is an orange-brown precipitate
what transition metal hexa-aqua complexes dissolve in excess ammonia
Cu 2+
Cr 3+
