Page 28 - Curriculum Visions Dynamic Book

Magnesium (Mg)
Element 12. A silvery-white, soft and reactive member of the alkaline earth metals, group 2 in the Periodic Table. It is the eighth most common element in the Earth’s crust.
Magnesium is very reactive, never found as a native element and quickly tarnishes in air.The oxide coating
then protects it from further reactions with air and water (making it appear unreactive) unless the surface is cleaned off. Magnesium burns with an intense white flame.
Discovery
Magnesium was first identified as an element by Joseph Black in 1755 but not isolated until 1808 by Sir Humphry Davy in England.That was done by electrolysis of magnesium oxide (MgO).
Key facts...
Name: magnesium
Symbol: Mg
Atomic number: 12
Atomic weight: 24.31
Position in Periodic Table: group 2 (2) (alkaline
earth metal); period 3
State at room temperature: solid
Colour: silvery-white
Density of solid: 1.74 g/cc
Melting point: 650°C
Boiling point: 1,107°C
Origin of name: from the Greek word Magnesia,
a district of Greece.
Shell pattern of electrons: 2–8–2
Technology
It is the lightest metal that is regularly used in construction (lighter than aluminium) and is widely used in aircraft and for space vehicles. It is alloyed with aluminium, zinc and manganese to improve its strength.
 A cleaned strip of magnesium ribbon burns in air with an intense white light.The result is white magnesium oxide.
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