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DM chemistry OCR B
Terms in this set (40)
d-block element that forms an ion with an incomplete d sub shell
physical properties of transition metals
high melting points
high boiling points
transition metals when soil
exist as giant metallic latices containing delocalised electrons which conduct electricity
variable oxidation states
the 4s orbitals electrons are lost first- due to them being the highest occupied energy Level.
form Coloured compounds
when light is passed through a solution containing transition metal ions, some wave lengths of light are absorbed- colour observed is a mixture of wavelengths that have NOT been absorbed
transition metals can act as a catalyst
-provide a surface on which the reaction can take place (heterogenous catalyst)
-ability to change oxidation states by gaining or losing electrons, then bind to reactants and form an intermediate as part of a chemical pathway with a lower Ea.
transition metals forming ppts
transition metals in an aqueous solution react with sodium hydroxide (aq)= coloured ppts
pale blue + 2OH-= pale blue ppt
pink solution + 2OH-= Pink ppt (turns beige in the presence of air.
pale green solution + 2OH- = green ppt that turns a rusty brown at its surface standing in air.
pale yellow + 2OH-= rusty brown ppt.
is a transition metal ion bonded to one or more ligands by coordinate bonds
[Cu(H20)6]2+. Each water molecule donated a lone pair of electrons from its oxygen to the CU2+ to form a coordinate bond.
molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond.
total number of coordinate bonds formed between a central metal ion and its ligand
ligand donates only ONE pair of electrons to the central metal ion to form a coordinate bond.
when there are 6 coordinate bonds attached to the central ion. in a 3D shape
all bonds are 90 degrees
- cis/trans isomerism
reaction in which one ligand in a complex ion is replaced by another ligand
Cu2+ and ammonia
4 water ligands are replaced by 4 ammonia ligands
pale blue solution-> deep blue solution
Cu2+ and HCl
6 water ligands are replaced by only 4Cls due to them having a greater repulsion so fewer can fit around the complex ion
pale blue solution-> yellow solution
Co2+ and concentrated HCl
6 water ligands are replaced by 4Cl ligands
pink solution-> blue solution.
when a ligand can donate two pairs of electrons.
Standard electrode potential
Potential difference between a half cell and a standard hydrogen half cell at 298K, 1 mol dm3 solutions and 1 atm
The corrosion of iron
Any metal with a more negative electrode potential than iron. Will form positive ions instead of Fe, preventing rust.
Ways to prevent rusting:
Oil, paint, grease, sacrificial metal
Occurs when no plane of symmetry in octahedral complexes with multidentate ligands.
Rotate plane of polarised light by same degree
When does ligand substitution occur
Occurs if new complex formed is more stable than the previous complex
Water and ammonia as ligands
Ammonia is a more stable ligand than water so will replace it
Ligands at 90° to eachother
Ligands at 180° to eachother
Standard cell potential
Positive terminal- negative terminal
Use of salt bridge
Find out the concentration of a coloured solution
Caused by some frequencies of light being absorbed
Where an element is both reduced and oxidised in same reaction
High density of transition metals
Electrostatic forces of attraction between ions and electrons cause it to be tightly packed
high melting point
Electrostatic forces of attraction require lots of energy to overcome
Free electrons can carry a current
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