7th Period Of The Periodic Table Complete

For the last fifty or so years, the periodic table has been incomplete. Elements after uranium on the periodic table have been synthesized for the past few decades, but there were always a few missing blocks in the periodic table. These elements, with atomic numbers of 113, 115, 117, and 118 comprise the missing parts of period 7 – the lowest row – of the periodic table. Now, IUPAC, the International Union of Pure and Applied Chemistry, has announced the verification of the discoveries of the last four elements of the seventh period of the periodic table.

With the announcement of the verification of discovery for these elements, they will get a name. Currently elements 113, 115, 117, and 118 are known as Ununtrium, Ununpentium, Ununseptium, and Ununoctium, respectively. What these elements will be named depends on the proposals by the discoverers of these elements.

Element 113 was discovered by researchers at the RIKEN laboratory in Japan, and these researchers will be able to propose a name and atomic symbol for their discovery. Elements 115, 117, and 118 were discovered through a partnership between the Joint Institute for Nuclear Research in Dubna, Russia, Lawrence Livermore National Laboratory in California, and Oak Ridge National Laboratory in Oak Ridge, Tennessee. Researchers at these three laboratories will propose names and atomic symbols for these three elements.

It should be noted that Lawrence Livermore National Laboratories and the Joint Institute for Nuclear Research in Dubna each have their own element named after them: Lawrencium and Dubnium, with atomic numbers 103 and 105, respectively. Having element 113, 115, and 118 named after Oak Ridge National Laboratory wouldn’t be a bad proposal, and would be rather fitting given the laboratory’s influence on the last half-century of physics.

Of particular interest is the naming of element 118. Because element 118 falls within group 18 of the periodic table, it is a noble gas, with a particular naming pattern. each of the elements in group 18 end with the suffix ~on, instead of the suffix for the rest of the periodic table, ~ium (helium is the exception to this rule due to historical precedent). Whether element 118 will use the ~on or ~ium suffix is up to debate; current IUPAC rules say all new elements should end with ~ium, but recommendations have been published to name all group 18 elements with the ~on suffix.

This is not the end of the periodic table by any means. It is possible that elements with higher atomic numbers can be synthesized. However, experiments to synthesize element 119 have so far come up short, and the predicted properties of element 119 put it at the limits of what current technology is able to detect.

40 thoughts on “7th Period Of The Periodic Table Complete

      1. Increasing views from people who came to read the article in the first place? Or increasing views from people coming back to reply to comments? Because I’d be surprised if they didn’t have Adblock anyway (I do, obviously).

        1. Hackaday is one of a hand full of sites for which I have turned off my ad blocker. They don’t have annoying intrusive ads, and my hope is that if people would do this for sites they wish to support that don’t have intrusive advertisements, the web sites would learn what is acceptable advertising and what crosses the line into the unacceptable. Blocking everything doesn’t get that point across.

  1. “it is a Nobel gas”

    It’s not Nobel, it’s “noble,” which came from a German translation implying that it doesn’t react.

    That being said, getting up to the 7th period like that, things don’t exactly follow periodic table behavior anymore, since you’ve basically just got this massive glob of protons/neutrons and a cloud of electrons around it. So in fact choosing “where” to put those guys is more just a historical idea rather than indicating anything about its underlying chemistry.

    1. Previously noble gases were called ‘inert gasses’, and the change was made when it was found they did react with something. In the 1960s, I think. ‘Noble’ just means they are fussy what they react with. [grin]

      1. … Kindof. The group 18 elements had been called noble gases for a long time before that. It’s just that “inert gases” was used interchangeably, until people were able to get the biggest noble gases to interact with the most reactive elements: e.g. xenon hexafluoride, at which point “inert gas” fell out of favor. The “noble gas” term came from the analogy to “noble metals,” a term which reaches back to alchemy days.

        It should be noted that helium and neon are still at this point “inert”, which just stresses my point that as you go down the periodic table, the “periodic” behavior fades : by the time you get even 4-5 rows down on the periodic table, the electron configuration gets so complex that you can’t just simplify things anymore.

      1. No, that’s very wrong. You’re off by a few orders of magnitude.

        Superheavy nuclei typically have half-lives of milliseconds-to-seconds, not nanoseconds. The shortest half-life of all of these guys is around ~1 ms. The reason it’s hard to study the chemistry of these nuclei is because you can’t produce enough of them fast enough.

  2. “Having element 113, 115, and 118 named after Oak Ridge National Laboratory wouldn’t be a bad proposal”

    115, 117 and 118 surely? 113 is RIKEN’s.

    Also, it is noble gas. Not Nobel >.>

  3. Oakium, Ridgium, Nationalum, and Laboratorium, sounds nice! Actually wonder if Oak or Oak Ridge sounds nice in Latin, might be an idea. Rikenium would be the first one named after an acronym, for 113.


    Let’s hope every one of them gets a different name. Those temporary names are easily confused with one another and almost unpronounceable, or should I say ununpronouncable to mimic these names.

    It’d be interesting to know how long these elements survived before decaying and what each decayed into.

    1. The temporary names are based on the atomic number and follow a fixed set of rules which is why they’re so similar sounding since only 1 digit differs and you have 2 repeated digits. The rules are quite simple though so once you know what each digit means then you can work out what element it is referring to. https://en.wikipedia.org/wiki/Systematic_element_name

      Ununtrium = Un-un-tr(i)-ium = 113
      Ununpentium = Un-un-pent-ium = 115
      Ununseptium = Un-un-sept-ium = 117

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