Transition Metals Flashcards
What are transition metals?
Metals that can form one or more stable ions with an incomplete d sub-shell
Why are Sc and Zn d-block elements, yet not transition metals?
Their highest energy electron is in the de subshell
Not trabsition metals because do not form an stable ipn with an incomplete d subshell
What are four characteristic properties lf transition metals that arise due to their incomplete d subshell?
Complex formation
Catalytic activity
Variable oxidation states
Formation of coloured ions
What is a complex?
A central metal ion that is surrounded by ligands
What is a ligand?
A molecule or ion that forms a co-ordinate bond with a transition metal, by donating a pair of electrons
What are the three types of ligands?
Monodentate, bidentate, multidentate
What is a monodentate ligand?
A molecule or ion that donates one pair of electrons to the central metal ion to form one coordinate bond
Give four common monodentate ligands, and state where their lone pair of electrons is
Water- on the oxygen
Ammonia- on the nitrogen
Chloride ions- on the chloride
Cyanide ion- on the carbon
What is a bidentate ligand?
Molecules or ions that have two atoms, that can each donate a pair of electrons to the central metal ion to form two different coordinate bonds
What is a multidentate ligand?
A molecule or ion that has more than two atoms that can each donate a pair of electrons to the central metal ion to form more than two coordinate bonds
Give the name of the main multidentate ligand, how many coordinate bonds can ot form?
EDTA 4-
Can form six bonds
What is a coordinate number?
The number of coordinate bonds to the central ion in a complex
What are the four common shapes of complexes, and their bond angles and coordinate numbers?
Octahedral- 90, 6 bonds
Tetrahedral- 109.5, 4 bonds
Square planar- 90/180, 4 bonds
Linear- 180*, 2 bonds
What shape do complexes containing water ligands usually have?
Octahedral
What shape do complexes containing ammonia oigands usually have?
Octahedral
What shape do complexes containing chloride ligands usually have?
Tetrahedral
Why is there a difference between the shape of complexes containing chloride ligands and ammonia/water ligands?
Chlorine ions are much bigger than water or ammonia molecules
What shape do complexes containing copper(I) ligands usually have?
Linear
What shape do complexes containing silver(I) ligands usually have?
Linear
What is the complex product when silver chloride or silver bromide is dissolved in ammonia? What shape complex is it?
[Ag(NH3)3]+
Linear
What transition metals usually form complexes with square planar shapes?
Ni, Pt, Pd
Why do transition metals have coloured ions?
Transitipn metal ions can absorb a certain frequency of visible light
This causes d- subshell electrons to be promoted (as they gain energy)
The remaining frequencies of light are transmitted- and the ion appears this colour
What colour are aqueous copper (II) ions and why?
Blue
Cu 2+ ions absorb certain frequencies of visible light
D electrons are promoted
Remaining frequencies are transmitted in the blue area of the visible spectrum
What is the difference in d- orbital energy between transition metal atoms and in complexes?
In transition metal atoms, all d-orbitals have the same energy
In complexes, the d orbitals split depending on the coordination number. So some orbitals have more energy than others. The orbital split creates an energy gap (ΔE)