How many elements can be made?

Since the 1940's scientists have been synthesizing new elements with atomic numbers greater than 92, the so-called transuranium elements.

Just how many elements can we make?

Read more in the September 2012 edition of AUS-e-NEWS.

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Element 118

In 1998, Robert Smolanczuk published some calculations which suggested that it could be possible to produce element 118 by fusing lead with krypton. In 1999, Lawrence Berkeley National Laboratory (LBNL) scientists reported the successful production of element 118 (given the temporary name ununoctium and temporary chemical symbol Uuo) by fusing lead-208 and krypton-86: 


86
36Kr + 208
82Pb → 293
118Uuo + n

Unfortunately, researchers, including LBNL scientists, were unable to duplicate theses results, and in 2002 the director of the laboratory announced that the original claim of the discovery of element 118 (ununoctium) had been based on data that was fabricated by a researcher and was not based on the results of a scientific investigation.

In 2006, researchers at the Joint Institute for Nuclear Research (JINR) and Lawrence Livermore National Laboratory of California announced that they had indirectly detected several nuclei of ununoctium-294, produced by colliding californium-249 atoms and calcium-48 atoms:

249
98Cf + 48
20Ca→ 294
118Uuo + 3n

However, in 2011 the International Union of Pure and Applied Chemistry (IUPAC) said the results did not meet the criteria for the announcement of the discovery of a new element.

Further Reading
Isotopes 
History of the Periodic Table

Suggested Study Questions

1. Give the atomic number for each of the following isotopes:
   • calcium-48
   • krypton-86
   • lead-208 
   • californium-249
   • ununoctium-294
2. Give the mass number for each of the following isotopes:
   • calcium-48
   • krypton-86
   • lead-208 
   • californium-249
   • ununoctium-294
3. Give the number of protons in the nucleus of each of the following isotopes:
   • calcium-48
   • krypton-86
   • lead-208 
   • californium-249
   • ununoctium-294
4. Give the number of neutrons in the nucleus of each of the following isotopes:
   • calcium-48
   • krypton-86
   • lead-208 
   • californium-249
   • ununoctium-294
5. It has been suggested that element 120 with a mass number of 302, and the temporary name unbinilium and temporary symbol Ubn, could be produced by bombarding plutonium-244 with iron-58. Write a possible equation for this reaction.
6. It has also been suggested that element 120 (unbinilium, Ubn) with a mass number of 302 could be produced by fusing uranium-238 and nickel-64. Write a possible equation for this reaction.
7. If unbinilium-302 were to be produced by fusing californium-248 with another atom, what would be the most likely element to use? Justify your answer by writing an equation for the equation.
8. What is the most likely product of the reaction in which californium-249 atoms are fused with titanium-50 atoms? Justify your answer by writing an equation for this reaction.
9. Based on your understanding of the arrangements of elements within the Periodic Table, which group do you think ununoctium would belong to? What would you predict the physical and chemical properties of ununoctium to be?
10. Before 1979, element 118 had been known as eka-emanation or eka-radon because radium "emanation" is an old name for the element radon, so-called because Friedrich Ernst Dorn first noticed that radium compounds emanate, or emit, a radioactive gas, and "eka" was the prefix used by mendeleev when constructing his Periodic Table to denote an unknown element 1 place down in the same Group. Give the current names for the elements which were originally known as:
• eka-caesium
• eka-iodine
• eka-boron
• eka-aluminium
• eka-manganese
• eka-silicon

Lithiated Graphite in Fusion Reactors

Nuclear fusion powers the stars and could be used to supply clean energy on Earth. A nuclear fusion plant would produce ten times more energy than a conventional nuclear fission reactor.

Scientists have been investigating the "plasma-material interface", the region in a fusion reactor where the inner lining cones into contact with the extreme heat of the plasma. A major challenge in finding the right coatings to line fusion reactors is that the material changes due to extreme conditions inside the reactors where temperatures can reach millions of degrees.

One such lining material uses lithium which is applied to the inner graphite wall of the reactor and diffuses into the graphite creating an entirely new material called lithiated graphite.
During a fusion reaction, some of the deuterium fuel atoms strike the inner walls of the reactor and either "pumped", causing them to bind with the lithiated graphite, or returned to the core and recycled back to the plasma.
The intense thermal energy inside the reactor causes tiny micro- and nano- scale features to "self-organise" on the surface of the lithiated graphite under normal plasma-surface interaction conditions. The surface only continues pumping for a few seconds before being compromised by damage induced by the extreme internal conditions.

Reference:
Purdue University (2010, July 27). Promise for nuclear fusion test reactors, findings show. ScienceDaily. Retrieved July 28, 2010, from http://www.sciencedaily.com­ /releases/2010/07/100727142415.htm

Study Questions

1. Define nuclear fusion.
2. Write an equation to represent a nuclear fusion reaction that might take place in a sun.
   
3. Define nuclear fission.
4. Write an equation to represent the nuclear fission of uranium-235.
   
5. How are deuterium atoms similar to hydrogen atoms?
6. How are deuterium atoms different to hydrogen atoms?
7. Name another isotope of hydrogen and give its symbol.
8. Name two allotropes of carbon.
9. Discuss the ways in which the two allotropes are the same.
10. Discuss the ways in which the two allotropes are different.
    
11. Draw a structure for graphite.
12. Use the drawing above to describe how lithiated graphite might be formed.
13. Discuss how deuterium atoms in the fuel plasma could bind to lithiated graphite.
    

Element 114

About 10 years ago, scientists in Dubna, Russia, reported the observation of element 114. Scientists at Berkeley, USA, and GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt Germany have also reported observations of element 114.

In the most recent GSI experiment using the 120 meter long GSI particle accelerator, the scientists fired calcium ions onto a plutonium coated foil. The nuclei undergo fusion to form the nucleus of the new element. The atoms of element 114 were then separated from the other products of the reaction and identified on the basis of the radiation emitted during their decay. Two different isotopes of element 114 were identified with mass numbers 288 and 289. The measured half-lives are of the order of one second.

Russian reports on the creation of elements up to atomic number 118 are yet to be confirmed.

Reference:
Helmholtz Association of German Research Centres (2010, June 22). Chemical element 114: One of heaviest elements created. ScienceDaily. Retrieved June 23, 2010, from http://www.sciencedaily.com­ /releases/2010/06/100622102347.htm

Study Questions

1. What is the atomic number of the element 114?
2. What are the atomic numbers of calcium and plutonium?
3. Define the term atomic number.
4. Write an equation to represent the fusion of calcium and plutonium.
5. What is meant by the term isotope?
6. For each of the isotopes of element 114 in the article above, give the atomic number, mass number, number of protons, number of neutrons, and number of electrons in an atom of each isotope.
7. Write a nuclear equation for the decay of each isotope of element 114 assuming it undergoes beta decay.
8. Write a nuclear decay equation for the decay of each isotope of element 114 assuming it undergoes alpha decay.
9. What is meant by the term half life?
   
10. If the half-life an isotope of element 114 is assumed to be 1 second, what percentage of the original isotope will be present after 10 seconds?