Flashcards in General Deck (26)
What are transition metals?
These are metals that have partially filled d orbitals or form ions with partially filled d orbitals
What is pairing energy?
The energy required to place 2 electrons in one orbital. This requires energy as this causes repulsions.
Describe the order of occupation of orbitals
1s, 2s, 2p, 3s, 3p, 4s, 3d 4p
The 3d orbital is higher in energy than the 4s orbital
4s is filled first and empties first
What energy to the 3d orbitals have in relation to each other?
They are degenerate
This means they all have the same energy
Which elements do not follow the filling orbital rules?
Cr has the electron configuration: 3d54s1
Cu has the electron configuration: 3d104s1
One of the s electrons have moved into the d orbitals
This is because this maximise angular momentum and avoids repulsions in the 4s orbital from pairing energy
What are the 5 d orbitals?
dyz, dxy, dxz, dz2 and dx2-y2
Why are d orbitals bad at shielding?
They are bad at shielding valence electrons due to their shape
Why is Zn not considered a transition metal?
Zn and Zn2+ both have d10 configuration which means it's d orbitals are completely filled
Therefore it is not considered a transition metal
Describe the trend in ionisation energy
Increase from Ca to Cr (d1-d4) as an electron is removed from singly occupied orbitals
Decrease at Mn (d5) as electron has been removed from doubly occupied orbital
Increase from d6-d10
Why is there a difference in energy between d1-d5 and d6-d10
There is a difference in energy due to pairing energy
Why are doubly occupied orbitals easier to remove from?
The electrons in doubly filled orbitals will experience repulsions and so less energy is required to remove them
Describe the trend in atomic radius
The atomic radius from Li-F decreases due to increase in zeff
Anomalous increase at Mn- double filled orbital as repulsion are more significant than zeff therefore radius increases
Describe the trend in orbital size
As n increases, orbital size increases
What is the lanthanide contraction?
D orbitals are poor at shielding so they cause anomalous trends in atomic orbital size
What is a metal complex?
This is a Lewis acid which acts as a central metal ion with a number of Lewis bases which are the ligands
What is a donor atom?
This is the atom in the ligand that forms the bond to the central metal atom by donation of a pair of electrons
What is coordination number?
This is the number of ligand donor atoms to which the central metal atom is directly bonded
Describe the elemental abundances in the earths crust, the sea, and the human body
Earths crust- lots of Fe
Sea water- even distribution
Human body- lots of transition metals- higher conc- as many TM are biologically necessary
Describe the applications of transition metals
- structural materials- Fe alloyed with Cr, V, MO, Ni, Ti
- electrical conductors- cu
- Batteries- MnO2, Ni, Zn
- magnetic materials- Fe+, Co, Ni, Fe2O3 or CrO2
Catalyst- Co, Cu
What is a chelate?
A complex containing a polydentate ligand is called a chelate
What is a chelating ligand?
Polydentate ligands are collectively known as chelating ligands
What factors determine coordinating number?
1) The size of the central atom (large means more ligands)
2) the steric interactions between the ligands
3) the electronic interactions
What charge can coordination complexes have ?
They can be neutral or a salt
What charge can ligands have?
They can be neutral or anionic
How do you write the formula of a complex?
Formula in square brackets
Metal ion first then anionic ligands and then neutral ligands
Cations come before anions