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Elements, renaming
Elements, renaming
Since the 1950s new elements
have been discovered in the
United States, Germany and Russia. However, no one agreed on what
to call them. In part this was because people could not agree on who first discovered each element. The person who discovers a new element has the right to give it a name.
International committees to name elements have also not met with success. For example, they rejected the U.S. naming of element 106 as seaborgium for Nobel prize winner Glenn T. Seaborg. As a result, the American Chemical Society used
a largely different group of names from those in other countries. This problem was resolved in 1997. As a result, the official names and symbols of elements 101 to 109 are: 101, mendelevium (Md); 102, nobelium (No); 103, lawrencium (Lr); 104, rutherfordium (Rf); 105, dubnium (Db); 106, seaborgium (Sg); 107, bohrium (Bh); 108, hassium (Hs); and 109, meitnerium (Mt).
Emulsion
A suspension of one liquid in another. The suspension is in the form of droplets. In an emulsion the two liquids must not be able to mix (immiscible).
Erbium (Er)
Element 68. A greyish-silver rare- earth metal and one of the lanthanides on the periodic table.
Discovered in 1843 by Carl Gustaf Mosander, it is important in fibre-optic telecommunications.
Europium (Eu)
Element 63 on the periodic table. A rare-earth metal and one of the lanthanides, discovered in 1896 by Eugène-Anatole Demarçay.
F
Fermium (Fm)
Element 100 on the periodic table. An artificial and radioactive element of the actinide series. It is a transuranium element.
Fermium was discovered by Albert Ghiorso in 1952.
Fission
The breakdown of the structure of an atom.
Fission is popularly called ‘splitting the atom’ because the atom is divided into approximately two other nuclei (singular is nucleus). It is different from, for example, the small change that happens when radioactivity is emitted.
 Fission – The chain reaction of uranium fission.
 Fluorine – Chains of units like the one shown below form solid polytetrafluoroethene. The fluorine atoms shield the carbon atoms that make the chain (polymer). Thus the carbon atoms form a polymer that is shielded from reaction by the fluorine: the secret of Teflon’s® non-stick success.
Fluorine (F)
Element 9 on the periodic table. The lightest halogen (group 7 element).
A pale yellow gas slightly heavier than air, fluorine is the most reactive chemical element.
It combines with all other elements except helium, neon and argon.
The French chemist Henri Moissan discovered fluorine in 1886.
It is mainly found as the mineral fluorite – calcium fluoride. It also appears in bones and
teeth. Adding fluoride to water has become popular because it helps teeth resist decay.
Fluorine is an extremely poisonous gas.
Barium-142
Energy
A neutron
A neutron
Uranium-235
A neutron
Krypton-92
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