transition metals Flashcards
why zinc ions are colourless
Zn2+ has a complete D subshell
so electrons cannot be promoted to a higher energy level
why scandium and zinc are not transition metals
transition metals form an ion with an incomplete d shell
scandium and zinc are not transition metals
Sc3+: 1s2 2s2 2p6 3s2 3p6
Zn2+: 1s2 2s2 2p6 3s2 3p6 3d10
Sc3+ has an empty d shell
Zn2+ as a dull d shell
charge of EDTA
4-
which type of bonding exists within [Cr(H2O)6]3+
dative covalent and covalent
the six characteristics of transition metals
hard solids
high melting and boiling temperatures
can act as catalysts
form coloured ions and compounds
form ions with incompletely filled d shells
ligand definition
a species that uses a lone pair of electrons to form a dative bond with a metal ion
co ordination number definition
the number of dative bonds in the complex
name of water in complex
aqua
name of hydroxide in complex
hydroxo
name of ammonia in complex
ammine
name of chloride in complex
chloro
name of cyanide in complex
cyano
name of iron in negative complex
ferrate
name of copper in a negative complex
cuprate
name of silver in a negative complex
arginate
the order of complex ion name
number of ligand
name of ligand
name of the metal ion
oxidation number of the metal ion
if there are two ligands, which way should you order them?
alphabetically
monodentate ligand
a ligand that forms one dative bond from a lone pair of electrons with a metal ion
bidentate ligand
a ligand that forms two dative bonds with a metal ion
e.g. NH2CH2CH2NH2
1,2- diaminoethane: abriviated to en
has optical isomers
complex stability
id total number of species (moles) increases across the reaction then stability increases.
entropy increases because ΔS system increases
formation of products is favoured
shape of complex with 6 ligands
octahedral
90 degrees
shape of complex with 4 ligands
tetrahedral
109.5 degrees
shape of complex with two ligands
linear
180 degrees
why chloride ion is usually tetrahedral in shape
it is in period 3 so has a large ionic radius
there is insufficient room around the central atom
shape of cis platin
square planar
reason cis platin is used more than trans platin
trans platin is less effective in treating cancer and is more toxic
origin of color in complexes
d shell splits into two levels with different energies
electrons in lower energy absorb energy and promoted to a higher level
amount of energy absorbed depends on the difference between the two levels
what causes change in colour of transition metal ions
change in oxidation number
change in ligand (ligand exchange)
change in co ordination number
