Page 9 - Curriculum Visions Dynamic Book

PtseePlatinum;P useePlutonium Radium (Ra)
Element 88.This silvery-white metal is the heaviest radioactive element
of the alkaline earth metals in group 2 in the Periodic Table. It is a very reactive element. It rapidly tarnishes to black when exposed to the air. Radium decomposes in water.
Radium luminesces (glows in the dark) due to its radioactivity. Radium is over a million times more radioactive than the same amount of uranium.
Discovery
Radium was discovered in France in 1889 by Pierre Curie, Marie Curie and G. Bémon.This came about when Marie Curie noticed that the radioactivity of pitchblende was up to five times greater than that of the uranium and polonium it contained.
Technology
Radium was used as a mixture with zinc sulphide to make luminous paint. That stopped when the dangers of using radium were recognised. It
is now not widely used.
Geology
It occurs with uranium ores such
as pitchblende because it is a natural decay product of uranium. It is also found in the mineral monazite.
Biology
It is not found in living things. However, because radiation can destroy cells, radium (which emits gamma rays) found an important use in medicine as a way of treating cancer by focusing radiation on tumours and destroying them. In recent times it has been replaced by cobalt-60.
Key facts...
Name: radium
Symbol: Ra
Atomic number: 88
Atomic weight: 226
Position in Periodic Table: group 2 (2) (alkaline
earth metal); period 7
State at room temperature: solid
Colour: silvery-white
Density of solid: 5.0 g/cc
Melting point: 700°C
Boiling point: 1,140°C
Origin of name: from the Latin radius, meaning ray Shell pattern of electrons: 2–8–18–32–18–8–2
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