subject title check
24 transition elements date
transition elements d-block elements which form one or more stable
ions with an incomplete d subshell
Sc and Zn are not classed as transition elements because they
only form one ion
shape of orbitals
properties of transition elements
1) variable oxidation states
-3d and 4s sub-shells have similar energy
-so similar amount of energy is needed to remove a different
number of electrons
-when transition elements form ions, electrons of 4s sub-shell
is lost first, followed by the 3d electrons
2) behave as catalysts
-due to their ability to form ions with more than one stable
oxidation state, and because they contain vacant d orbitals
-can accept and lose electrons easily to go from one oxidation
state to another (can catalyse redox reactions)
-can form dative bonds with ligands due to vacant d ortibals
3) form complex ions
-complex is a molecule/ion formed by a central metal atom/ion
surrounded by one or more ligands
-vacant d orbitals are energetically accessible (not too high
in energy), so dative bonds can be formed between transition
element & ligands
4) form coloured compounds
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date
ligands & complex formation
ligand a species that contains a lone pair of electrons that forms a
dative covalent bond to a central metal atom/ion
complex a molecule/ion formed by a central metal atom/ion
surrounded by one or more ligands
coordination number the number of dative bonds formed between the
central metal ion and the ligands
- some ligands are neutral, others
·
are charged
.
-if coordination number is 6, shape is
4
octahedral
-if coordination number is 4, shape is
either tetrahedral or square planar
different ligands can form different numbers of dative bonds to the
central metal ion in a complex
monodentate ligands bidentate ligands
polydentate ligands
bidentate ligands form two dative bonds because each ligand consists
two atoms with lone pairs of electrons
1,2-diaminoethane (H2NCH2CH2NH2) is written as 'en'
ethanedioate ion (C2O4 ) is writer as 'ox'
2
1
geometry of transition metal complex
complexes with four linear (180 ) O
square planar (90 ) (mostly CN )
⑧
chloride ions are
mostly tetrahedral
(chloride ligands are tetrahedral (109.5 ) O
octahedral (90 )
large, so only four
will fir around the
central metal ion)
Copyright 2021. 해움. All rights reserved.
24 transition elements date
transition elements d-block elements which form one or more stable
ions with an incomplete d subshell
Sc and Zn are not classed as transition elements because they
only form one ion
shape of orbitals
properties of transition elements
1) variable oxidation states
-3d and 4s sub-shells have similar energy
-so similar amount of energy is needed to remove a different
number of electrons
-when transition elements form ions, electrons of 4s sub-shell
is lost first, followed by the 3d electrons
2) behave as catalysts
-due to their ability to form ions with more than one stable
oxidation state, and because they contain vacant d orbitals
-can accept and lose electrons easily to go from one oxidation
state to another (can catalyse redox reactions)
-can form dative bonds with ligands due to vacant d ortibals
3) form complex ions
-complex is a molecule/ion formed by a central metal atom/ion
surrounded by one or more ligands
-vacant d orbitals are energetically accessible (not too high
in energy), so dative bonds can be formed between transition
element & ligands
4) form coloured compounds
Copyright 2021. 해움. All rights reserved.
, subject title check
date
ligands & complex formation
ligand a species that contains a lone pair of electrons that forms a
dative covalent bond to a central metal atom/ion
complex a molecule/ion formed by a central metal atom/ion
surrounded by one or more ligands
coordination number the number of dative bonds formed between the
central metal ion and the ligands
- some ligands are neutral, others
·
are charged
.
-if coordination number is 6, shape is
4
octahedral
-if coordination number is 4, shape is
either tetrahedral or square planar
different ligands can form different numbers of dative bonds to the
central metal ion in a complex
monodentate ligands bidentate ligands
polydentate ligands
bidentate ligands form two dative bonds because each ligand consists
two atoms with lone pairs of electrons
1,2-diaminoethane (H2NCH2CH2NH2) is written as 'en'
ethanedioate ion (C2O4 ) is writer as 'ox'
2
1
geometry of transition metal complex
complexes with four linear (180 ) O
square planar (90 ) (mostly CN )
⑧
chloride ions are
mostly tetrahedral
(chloride ligands are tetrahedral (109.5 ) O
octahedral (90 )
large, so only four
will fir around the
central metal ion)
Copyright 2021. 해움. All rights reserved.
