Researchers from Lund University (Sweden) presented evidence which may confirm the existence of a new chemical element, with atomic number 115. This discovery could change the shape of the Periodic Table of the elements.
Chemical Elements and Periodic Table
Chemical elements are the atoms which constitute all matter, and whose nature cannot be altered with chemical reaction.
Examples of common chemical elements we are familiar with are carbon (C), oxygen (O), iron (Fe), calcium (Ca), etc.
Each element is characterized by an atomic number, which represents the number of protons which the element has. Hydrogen (H), for instance, is the lightest atom with just one proton (i.e. the atomic number is 1).
All chemical elements are presented in the periodic table; here they are arranged not just based on their atomic number but also on their properties.
Elements with atomic number between 1 and 94 occur in nature; elements with higher numbers, on the contrary, are not natural but were created synthetically in a laboratory.
Nuclear Reactions to Create New Atoms
The process used to synthesize new atoms is generally a nuclear reaction: We bombard an already existing element with a beam of appropriate atoms and/or particles (neutrons, protons) at high energy. This bombardment could lead to reactions between the nuclei of the two atoms, or the addition of neutrons and protons to an element (nuclear reactions). Consequently, the number of protons of the atom may change and, hence, the nature of the element itself may also change.
Generally to synthetize new heavier elements, we bombard a certain atom with another appropriate atom; as a consequence of the reaction, the two atoms merge together to form a heavier element (fusion).
Existence of New Atoms
As stated above, scientists have used nuclear reactions to synthesize several elements similar to those described above. Examples include the elements with atomic numbers of 114 and 116, subsequently named flerovium (Fl) and livermorium (Lv).
The list of new synthetic elements, however, could be further extended after the breakthrough results published in Physical Review Letters on the 28th of August 2013. In this paper, scientists report new evidence for the existence of a new element, with atomic number 115.
The work was performed by several researchers of different countries, under the coordination of professor Dirk Rudolph, professor at the Division of Nuclear Physics at Lund University (Sweden). The main experiment was performed at the GSI Darmstadt facilities (Germany).
Atomic Number 115: Confirmation of the Existence
M.Sc. Ulrika Forsberg, PhD student and one of the scientists involved in the study, explains to Decoded Science:
“What we published now are the latest results in a huge amount of work which has been going on for several years and in several different research groups.
The first report on the 115 element dates back to 2004 (Dubna-Livermore collaboration); after that our group continued the investigation to confirm and prove definitively the existence of this element. What was done was to bombard americium (atomic number = 95) with calcium (atomic number 20); the nuclear reaction generated an element with atomic number of 115. This element is quite heavy and highly instable.
Three isotopes were seen, that is atoms with 172, 173 and 174 neutrons in the nuclei. This corresponded to atomic mass of 287, 288 and 289 respectively. In our particular experiment, we mainly studied the energy emitted by the isotope 288-115 and the daughter atoms formed by the decay of this element.
What we observed were the radiation emitted from the following atoms: roentgenium (280Rg), meitnerium (260Mt), bohrium (272Bh) and the atom with number 113 and mass 284 (which does not have a name yet). The radiation came in the form of alpha particles and photons. Then we compared the emitted energy with very accurate calculations.”
New Element in Periodic Table: Official Name?
This element does not have a proper name and an atomic symbol yet. According to M.Sc. Forsberg:
“There is a committee which officially approves the discovery of new elements; normally it is a Joint Working Group of members of the International Union of Pure and Applied Chemistry (IUPAC) and Physics (IUPAP). It is up to them now to decide if these evidences are sufficient to prove the existence of these elements or if they want something more. A very reasonable request would be more experiments of the same kind, to see more of the atoms and of the radation.
Whatever they decide, however, we achieved very important results, which move us a step closer to official recognition. Maybe the most important part is that we have shown that this method works and that such experiment is feasible. This is an important discovery for the world of chemistry and physics and will bring a change in the periodic table.”
Rudolph, D. et al. Spectroscopy of the Element 115 Decay . (2013). Accessed August 28, 2013.
D. Rudolph, et al. Spectroscopy of Element 115 Decay Chains. (2013). Physical Review Letters.
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