Page 10 - Curriculum Visions Dynamic Book

H see Hydrogen Hafnium (Hf)
Element 72. A silvery, soft, bendable metal belonging to the transition metals in the Periodic Table. Hafnium is very similar to zirconium in properties, and it is difficult to separate the two elements. Hafnium is very corrosion resistant. It is not especially rare, being 45th in order
of abundance in the Earth’s crust. It is an easily shaped metal with
a brilliant silvery lustre.
Discovery
It was discovered by Dirk Coster and George Charles de Hevesy in 1923 in Copenhagen, Denmark. It was named after Hafinia, which is the Latin name for Copenhagen.
Technology
Hafnium absorbs neutrons and goes into control rods in nuclear reactors.An alloy of tantalum, hafnium and carbon has a very high melting point (4,215°C) and holds other materials that are to be melted. For example, it helps in the manufacture of tungsten filaments. Because of its high melting point and corrosion resistance
it is also a structural material in nuclear power plants and nuclear submarines.
Geology
Hafnium is not found as a native element, but occurs mainly in zirconium minerals, where it makes up about 2% of the mineral.Alvite is a hafnium silicate mineral.
Biology
Hafnium is not found in living things and is not especially hazardous.
Key facts...
Name: hafnium
Symbol: Hf
Atomic number: 72
Atomic weight: 178.49
Position in Periodic Table: transition metal,
group (4) (titanium group); period 6 State at room temperature: solid Colour: silvery
Density of solid: 13.31 g/cc
Melting point: 2,227°C
Boiling point: 4,603°C
Origin of name: after the Latin name for the
city of Copenhagen (Hafnia)
Shell pattern of electrons: 2–8–18–32–10–2
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