Summary A* student notes -CIE A-level Chemistry - Unit 28 - Transition elements

TRANSITION METALS
Transition & block element which
elements -




form one or more stable ions
with an incomplete -subshell
·

Scadium and Zinc are not transition elements
scadium Zinc

only forms one ion
only forms one ion
-
-




-




ion has an
empty 3d orbitals
-

has a complete 3d subshell

-

The 3d subshell is made of d orbitals


3dxy 3d




Properties or
Yaens -
-variable oxidation states
>
-
behave as catalysts like normal metals
they form positive
-
-




S
form complexions ions
-




-
however
-form coloured they can form multiple
compoundsding
-




what different positive ions

since
they have ligands are present
various oxidation
they will have
different colours
states
they can act

as catalysts by gaining or
losing a
complexion is a molecule

electrons or ion with a central transition ion and
bonded dative covalent bonds
ligands by
Variable oxidation states
-
arise because the 3d and 4s subshells catalysts
are similar in variable oxidation states
energy
-




when ions 4s electrons between them
form
-




are
-


can move

lost first -
can
catalyse redoxreactions
-


the most common oxidation state is a

by electrons Vacant d orbitals
losing the 45
-


at the start of the period it is easierfor
-

when they form ions
They
all 3d electrons to be cost have vacant orbital
at the end of the period due to increased which are
energetically
-




its harder to remove electrons
nuclear
charge accessible
allows for dative bond with
ligands
-




-

donated pair of electrons
fills the emptya orbital

, complex ions
Geometry
complex - molecule formed by
or ion linear
central transition metal ion two
ligands
-


a

1800
surrounded
by one or more
-
HsN : -CuiNHs
ligands
if charged it is a complexion tetrahedral
-




transition element accepts electrons four coordinate bonds
-
-




into its d orbital
?

complex formation d7109 .
5

ligands form dative bonds
&
-




by donating a
pair of electrons
into o orbitals
go empty
-




CI
Square planar
Complexes with water and ammonia -




four coordinate bonds
and both
-


water amonia are -

Cis platin
neutral ligands



p. .
monodentate
ligands have one
-
-




come pair =
one bond
small so6 fit around
-


can
-


co-ordination number =
number of
dative bonds Octahedral
-
here it is 6
-

Six coordinate bonds
-

these complexes therefore have an -


900
octahedral shape
980 bond
angle
-




LIGAND EXCHANGE
complexes with hydroxide andehoridsions >
- when one
ligand is replaced with
negatively charged ligands
-
another
-


monodante -


Forms a MORE stable complex
-




hydroxides can fit 6 as only aresmall -




the ligands can be partially or
clorides fit 4 as
they are large fullyexchanged
-

can




Ligand Copper exchange
-

molecule or ion with one or more love -


when in solution it is

pairs of electrons copper hexaaqua
Blue solution
Monodentate [Cu(H20) s ]* >
-


bond
one love pair one
LAddition of OH-
-
-




Bidentate
-


two lone pairs - two bonds [u(H20)(OH) ] ,
- pare blue
precipitate
Polydentate Laddition of conc .

NH
multiple lone pairs multiple bonds
ba
=




e
-




[cu (NHs(H2O)c] deep -
on