Transition Metals (properties, complexes and shapes) Flashcards
Where are transition metals located in the periodic table?
Between group 2 and 3, in the d block because outer electron is found in the d-orbital
When transition metals form ions which orbital is emptied first and why?
4s
- the energy levels of 4s and 3d orbitals are very close together. When the 4s and 3d orbitals are filled, the energy levels swap over as expected. This happens due to the addition of electrons and their energies in the orbitals
Why are zinc and scandium not transition metals?
When forming ions (Zn2+ and Sc3+), scandium has no electrons in d-orbital and zinc has a full orbital. Hence they cannot form an atom/ ion with an incomplete d-orbital so are not transition metals.
What are the characteristic properties of transition metals?
They form coloured compounds/ions
Act as catalysts
Have variable oxidation states
Form complexes
What feature of transition metals gives rise to their characteristics?
Incomplete d-orbital
Why can Li+ and Na+ not be used as catalysts?
Only exist in one oxidation state
Why is the most common oxidation state of transition metals 2+?
4s electrons are the first to go
Why do transition metals form variable oxidation states?
4s and 3d are very close in energy - 3d electrons can easily be removed as well. This means that several ions can be formed by losing different amounts of electrons, all of which are stable.
What is a complex ion?
A metal ion surrounded by co-ordinately bonded ligands.
What is a ligand?
A molecule/ion that donates a lone pair of electrons to a central metal ion to form co-ordinate bonds.
What are the 3 main types of ligands?
Monodentate - has one atom that can donate a lone pair of electrons to form a coordinate bond.
Bidentate - Has 2 atoms, each donating a lone pair of electrons to form 2 coordinate bonds (each)
Multidentate - has many atoms, each donating a lone pair to for many coordinate bonds.
What is meant by the term coordination number?
Number of coordinate bonds formed with the central metal ion
What are examples of monodentate ligands?
Water
Ammonia
Chloride
Why does water act as a monodentate ligand despite having 2 lone pairs of electrons?
The lone pairs are very close together
What are examples of bidentate ligands?
Ethanedioate ion
Ethane-1,2-diamine
What is an example of a multidentate ligand?
EDTA4-
What does the shape of a complex ion depend on?
Size of ligands attached
Coordination number
Which ligand forms tetrahedral complexes?
Cl-
Which ligands form octahedral complexes?
H2O and NH3
Which metal atoms have square planar complexes?
Pt2+ and Ni2+
Which metal atoms have linear complexes?
Ag+
