PRESENTATION OUTLINE
Rodium was discovered in 1803 by William Hyde.
Rhodium is very hard,silvery,durable medal that has high reflectance.
Rhodium has a higher melting point and lower density than platinum.
Naturally occurring rhodium is usually found as the free metal.
Rhodium is a so-called noble metal.
Discovered in 1898 by Marie Curie and Pierre Curie.
Polonium has 33 known isotopes, all which are radioactive.
Polonium is a radioactive element that exists in two metallic allotropes.
The chemistry of polonium is similar to that of tellurium and bismuth.
The most stable class of polonium compounds are polonides.
Francium was discovered by Marguerite Perey in France in 1939.
Francium is the most unstable of the naturally occurring elements.
Francium is an alkali metal whose chemical properties mostly resemble those of caesium
It has been used for research purposes in the fields of biology and of atomic structure
There are 34 known isotopes of francium ranging in atomic mass from 199 to 232
Rhenium was the last element to be discovered having a stable isotope.
Rhenium is a silvery-white metal with one of the highest melting points of all elements
Rhenium is one of the rarest elements in Earth's crust with an average concentration of 1 ppb
Rhenium improves the properties of tungsten.
Very little is known about the toxicity of rhenium and its compounds because they are used in very small amounts
Helium is the second lightest element and is the second most abundant element in the observable universe
Helium is named for the Greek god of the Sun, Helios.
Sir William Ramsay, the discoverer of terrestrial helium.
Helium produced between 1930 and 1945 was about 98.3% pure (2% nitrogen), which was adequate for airships
Helium discharge tube shaped like the element's atomic symbol.
It is named after the continent Europe.
It is a moderately hard, silvery metal which readily oxidizes in air and water.
Europium is a ductile metal with a hardness similar to that of lead.
Europium is the most reactive rare earth element.
Europium is one of the elements used to make the red color in CRT televisions.
