Flashcards
OCR EEE - Transition elements, Complex ions, Ligand substitution and Stability constants
Cards in this deck (32)
- 1What is a transition metal?A d-block element that forms and ion with an incomplete d sub-shell
- 2Why are scandium and zinc not classed as transition elements?They don't have partially filled d sub-shells.
- 3Which sub-shell is filled first and which sub-shell are electrons lost from first?4s sub-shell because it has a lower energy than 3d sub-shell
- 4What are the properties of transition elements?1. Can form complex ions
2. They form coloured ions
3. They're good catalysts because they can change oxidation states by gaining or losing electrons.
4. They exist in variable oxidation states - 5What is a ligand?A molecule or ion that can donate a pair of electrons to a metal ion to form a coordinate bond
- 6What is a complex ion?A transition element bonded to one or more ligands by coordinate bonds
- 7What is the coordination number?Indicates the number of coordinate bonds to the central metal ion
- 8What is a monodentate ligand?Can only donate one pair of electrons to a metal ion to form a coordinate bond
- 9Examples of monodentate ligands1. Ammonia - NH3 (One lone pair on the nitrogen atom)
2. Chloride ions - :Cl
3. Water - Oxygen has 2 lone pairs of electrons but can only form one coordinate bond because the lone pairs are too close together.
4. Cyanide - :CN - 10What are bidentate ligandsCan donate 2 pairs of electrons to a metal ion to form two coordinate bonds
- 11Example of a bidentate liganden (ethane-1,2-diamine) - is a bidentate ligand because it has 2 amine groups and each has a lone pair of electrons which they can donate to form coordinate bonds
- 12What are multidentate ligands?Can donate more than one pair of electrons to form coordinate bonds with the metal ion
- 13Example of a multidentate ligand1. EDTA4- (2 lone pairs on nitrogen atoms and 4 lone pairs on oxygen atoms) can form 6 coordinate bonds with central metal ion.
- 14What is the shape and bond angle of a complex ion with a coordination number of 6?Shape - Octahedral
Bond angles - 90° - 15What is the shape and bond angle of a complex ion with a coordination number of 4?Shape - Tetrahedral
Bond angles - 109.5° - 16Some complexes show a square planar shape, name one example and the bond anglesCis-platin
Bond angles - 90° - 17Optical isomers only form when...Carbon atom is attached to different atoms or groups of atoms
- 18What are optical isomers also known as?Enantiomers
- 19What is cis-platin used for?1. Used to treat cancer
2. Prevents cancer cells from reproducing
3. Cis-platin binds to DNA and stops DNA from unwinding so DNA can't replicate - 20What is ligand substitution?When one ligand in a complex ion is replaced by another
- 21[Co(H2O)6]2+(aq) + 6NH3(aq) ==>[Co(NH3)6]2+(aq) + 6H2O(l)
- 22[Cr(H2O)6]3+(aq) + 6OH–(aq) ==>[Cr(OH)6]3–(aq) + 6H2O(l)
- 23[Cu(H2O)6]2+(aq) + 4Cl–(aq) ==>[CuCl4]2–(aq) + 6H2O(l)
- 24[Co(H2O)6]2+(aq) + 4Cl–(aq) ==>[CoCl4]2–(aq) + 6H2O(l)
- 25[Cu(H2O)6]2+(aq) + 4NH3(aq) ==>[Cu(NH3)4(H2O)2]2+(aq) + 4H2O(l)
- 26What is the function of haemoglobin?Transports oxygen around the body
- 27What metal ion can oxygen bind to in haemoglobin?Fe2+
- 28What ligand is replaced by oxygen?H2O is replaced by oxygen in the lungs
- 29How does carbon monoxide bind to Fe?1. Instead of water being substituted for oxygen it is substituted for carbon monoxide
2. Carbon monoxide binds more strongly than oxygen, this reaction is irreversible
3. This makes the Hb useless
4. Carbon monoxide causes organs to starve of oxygen - 30Why is water not included in stability constant equations?Because it is in large excess and is virtually constant
- 31How to write a stability constant[Products]
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[Reactants] - 32What does a large value of Kstab indicate?1. Position of equilibrium lies to the RHS.
2. Complex ion is stable and can be easily formed.
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- Chemistry Flashcards on OCR EEE - Transition elements, Complex ions, Ligand substitution and Stability constants, created by umer.sabir on 19/05/2014.
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