Page 51 - Curriculum Visions Dynamic Book

Zinc (Zn)
Element 30. A soft, easily shaped, blue–grey metal.Although zinc is found in the block of transition metals in the Periodic Table, it does not show the typical properties of those elements. It has a much lower melting point and the majority of its compounds are colourless. It is brittle at room temperature but is easily bent and shaped above the boiling point
of water. It is a good conductor of electricity and heat.When it burns,
it gives off white clouds of zinc oxide.
Discovery
Zinc was discovered by Andreas Marggraf in Germany in 1500.
Technology
Zinc was used for thousands of years before it was identified as an element. It has been alloyed with copper to produce brass since ancient times. Brass contains
Pieces of zinc
Key facts...
Name: zinc
Symbol: Zn
Atomic number: 30
Atomic weight: 65.39
Position in Periodic Table: transition metal, group
(12) (zinc group); period 4
State at room temperature: solid
Colour: blue–grey
Density of solid: 7.13 g/cc
Melting point: 419°C
Boiling point: 907°C
Origin of name: from the German word zink Shell pattern of electrons: 2–8–18–2
between 20 and 45% zinc, making a variety of types of brass. Brass is harder than zinc and is a good conductor of electricity. It is used for pins and contacts in switches, plugs and sockets. Bronze and solder also contain zinc, as do cheap dry batteries (zinc–carbon batteries).
Zinc forms a protective coating for steel, the combination being called galvanised iron. Zinc is attached to many iron structures to protect them.When securely fastened to iron, the zinc corrodes, leaving the iron untouched. In this role the zinc is called a sacrificial anode.
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