Transition metal
No description yet. This curated deck is ready for daily study.
Card preview (24)
define Ligand
• an ion, atom or molecule that can donate an electron.
Give 4 characteristics of transition metals
• complex formation • formation of coloured ions • variable oxidation state • catalytic activity
What does dentate mean
• the number of coordinate bond per ligand
Give 4 examples of monodentate ligands
• H20 • NH3 • Cl- • OH-
Describe the function of haemoglobin
• protein used to transport oxygen around the body in blood
Name the shape of the haemoglobin molecule
• octahedral
Describe the structure of Haemoglobin
• central Fe2+ ion • 4 nitrogen multidendate ligands • oxygen/water that coordinate bonds with the Nitrogen to allow transport of molecules around the body
Describe the action of haemoglobin in the lungs, and back.
• lungs: oxygen subs in the water ligand where oxygen conc is high to form oxyhaemoglobin. • oxyhaemoglobin gives up oxygen to a place where it’s needed, and water subs in again, taking back haemoglobin to the lungs to start over.
Explain why CO is a poisonous gas
• the water ligand will be replaced with CO ligand • CO has higher bonding affinity to haemoglobin, so not readily replaced oxygen • so O2 can’t be transported, leading to oxygen starvation
what type of octahedral complexes will show optical isomerism?
• with 3 bidentate ligands
When will octahedral complex ions show cis/trans isomerism
• Octahedral complexes with 4 ligands and the SAME type of 2 ligands of a different display.
When will it be considered a trans isomer?
• when the 2 different ligands are opposite to each other
When will the complex ions show cis isomerism?
• when the 2 different ligands are adjacent to each other.
When will square planar complex ions show cis/trans isomerism?
• when they have 2 ligands of the same type and 2 ligands of a different type. (basically, 2 Cl and 2 NH3 for eg)
What happens to the d orbital when ligands bond with the central metal ion?
• split into 2
describe what happens when ligands bond with central metal ions
• d-subshell splits • some orbitals gain energy, creating an energy gap.
Describe why transition metal complexes are coloured.
• ligand causes d orbitals to split into 2 • Electrons absorb energy • so electrons get excited, and are promoted to higher d orbitals • the unabsorbed light is seen as the complementary colour.
In what situation will a colour not be seen? why?
• complexes that have a completely full or empty 3d subshell. • because it means that no electrons can migrate to the higher energy level.
What is the relationship between the frequency and energy gap.
• the larger the gap, the higher the frequency of light (eg purple - blue range of visible light)
What is the colour of a transition metal dependant on? (3)
• type of ligand • shape of the ligand • oxidation state of the central metal ion
What does the frequency absorbed depend on?
the size of the energy gap.
What happens to the frequencies that are not absorbed?
• reflected or transmitted.
What characterises a transition element?
• a d-block element that can form at least one stable ion with a partially filled d-subshell
describe the electron configuration principle for transition elements.
• fill up singly first, then double up.