F325: Module 3: Transition elements Flashcards
I) What is a transition Element?
A transition element has at least one stable ion with an incomplete d sub-shell.
I) What are some of the characteristics of transition elements?
They form coloured ions due to their partially filled d orbital.
They have variable oxidation states.
They can act as catalysts.
They can form complex ions.
I) Why is Zinc (Zn) not a transition metal?
Zn can only form a 2+ ion.
The Zn2+ ion has a complete d orbital and so does not meet the criteria of having an incomplete d orbital in one of its ions.
I) Why is Scandium (Sc) not a transition metal?
Sc can only form a 3+ ion.
The Sn3+ ion has an empty d orbital and so does not meet the criteria of having an incomplete d orbital in one of its ions.
I) What is special about the electron configuration of Chromium and copper?
They both have 4s1 configurations (not 4s2).
This is to allow either a half filled or a filled d sub shell to be made.
A half or full filled d sub shell is more energetically stable.
I) Why are transition metals often good catalysts?
They can have different oxidation states, so they can gain or lose electrons in moving between these oxidation states, thus speeding up a redox reaction.
They provide sites at which reactions can take place, because that bond to a wide range of ions and molecules in solution and as solids.
I) Give some examples of industrial catalysts.
Fe is used in the production of ammonia.
V2O5 is used in the production of sulfur trioxide, used to make sulphuric acid.
Ni is used in the hydrogenation of alkenes.
I) Describe the 4 main precipitation reactions between a transition metal and sodium hydroxide.
Cu 2+ (Blue) +2OH- ==> Cu(OH)2 (Blue ppt)
Co 2+ (Pink) + 2OH- ==> Co(OH)2 (Blue ppt)
Fe 2+ (Pale Green) + 2OH- ==> Fe(OH)2 (Green ppt)
Fe 3+ (Yellow/orange) + 3OH- ==> Fe(OH)3 (Rusty Brown ppt)
