The murder of the jeweller |

	The murder of the jeweller
What’s the mystery?	The mystery revolves round a detective story which the students gradually solve. A jeweller has been murdered: the suspects are his metal suppliers but the motive and the culprit are initially unknown.
Domain(s)	Chemistry
Subdomain keywords	Electrochemical series of metals, properties and reactions of metals, periodic system of the elements.
Age group	14 to 18 years old.
Expected time for the mystery	Approximate time for teacher preparation: 30 min.Approximate time in classroom: two 45-min lessons.
Safety/supervision	The experiments use a five per cent solution of HCl: this is an irritant. Caution and protective gloves are needed.Disclaimer: the authors of this teaching material will not be held responsible for any injury or damage to persons or properties that might occur in its use.
Preparation and list of materials	Text of a detective story for each group of students, common chemical equipment (test tubes, pipettes, petri dishes and pincers), solutions (AgNO₃, Al₂(SO₄)₃, ZnSO₄, HCl: everything is diluted at, for example, five per cent concentration), solid metals (Zn, Al, and some silvery metal with a look and shape similar to silver, possibly Sn or Fe).
Learning objectives	Students learn about the redox properties of metals, which are the base of the electrochemical series of metals. This series of metals was first assembled by the Russian chemist N. N. Beketov in the 19th century, which is why it is sometimes called the Beketov’s series of metals, and it is aslo why we used his name in our story. V. V. Markovnikov was also an important Russian chemist of the 19th century.
Resources	You can find examples of reactions between reactive metals and salts of less reactive metals in the videos below: Reaction between copper and silver nitrate: Silver tree Silver Christmas tree Reaction between iron and copper sulphate: Chemistry Revision – Iron & Copper Sulphate solution Reaction between aluminium and copper sulphate: Placing aluminium foil into a solution of copper(II)sulphate with water and hydrochloric acid