The latest release of the Periodic Table (dated 28 November 2016) includes the recently added elements 113, 115, 117, and 118 with their names and symbols (see related News), the standard atomic weights 2013 (abridged to five significant digits) and the conventional atomic weights as published in PAC Vol. 88, No.3, pp. 265-291 (http://dx.doi.org/10.1515/pac-2015-0305), and for ytterbium, the standard atomic weight updated following the 2015 review (see related News). An interval in square brackets provides the lower and upper bounds of the standard atomic weight for that element. For users needing an atomic-weight value for an unspecified sample with disregard to the uncertainty, the conventional values are provided. No values are listed for elements which lack isotopes with a characteristic isotopic abundance in natural terrestrial samples.
By virtue of its work in relation with the chemical elements, IUPAC can dispense a periodic table that is up-to-date. IUPAC involvement covers various aspects of the table and data that it unveils, and several reports and recommendations, some quite recent, attest of that input.
In particular, IUPAC is directly involved in the following:
- establishing the criteria for a new element discovery
- defining the structure of a temporary name and symbol
- assessing claims resulting in the validation and assignation of an element discovery
- coordinating the naming of a new element, involving the research laboratory and allowing for public comments
- setting up precise rules for how to name a new element
- defining Group 1-18 and collective names
- determining which elements belong to Group 3
- regularly reviewing standard atomic weights
The table is yours to use. Details about the latest release are provided above. Details below provide multiple references to IUPAC journal in Pure and Applied Chemistry (PAC) and magazine Chemistry International (CI).
- Criteria for a new element discovery
Assessing if an element has been “discovered” is not a simple task. While reviewing the discovery profiles of the transfermium elements in the early 90s’, IUPAC and IUPAP set up to establish a series of criteria that must be satisfied for the discovery of an element to be recognized. See details in PAC 1991, Vol. 63, No. 6, pp. 879-886 (http://dx.doi.org/10.1351/pac199163060879) and PAC 1993, Vol. 65, No. 8, pp. 1757-1814 (http://dx.doi.org/10.1351/pac199365081757)
- Temporary name and symbol
While an element can have been claimed, before the claim has been validated and before the element is formally named, the element has a temporary name and symbol. The pertinent recommendations setting-up that systematic nomenclature was published in 1978; see PAC 1979, Vol. 51, No. 2, pp. 381-384; http://dx.doi.org/10.1351/pac197951020381
In result, that is how, in March 2016, element 113 was called ununtrium or with the symbol Uut.
The story behind the three-letter symbols is recounted in a feature prepared by Lars Öhrström and Norman Holden and published in Chem Int 2016, Vol. 38, No. 2, pp. 4-8; http://dx.doi.org/10.1515/ci-2016-0204
- Validation and assignation of an element discovery
Claims for the discoveries of new elements appear time to time in the scientific literature. IUPAC, along with IUPAP, is involved in assessing these claims. In result, IUPAC technical reports are released that review each pertaining references and recognize the laboratory(ies) whose claims fulfill the agreed criteria.
In 2016, two such reports have been released that cover elements 113, 115, 117, and element 118; See PAC 2016, Vol. 88, No. 1-2, pp. 139–153; http://dx.doi.org/10.1515/pac-2015-0502 and PAC 2016, Vol. 88, No. 1-2, pp. 155–160; http://dx.doi.org/10.1515/pac-2015-0501
- Naming new element
When the discovery of a new element has been validated and the priority for its discovery has been assigned, the naming process can begin. The Laboratory to which the discovery has been assigned is invited to propose a name and symbol. IUPAC will then review the proposal, and if agreed, after an additional 5-month public review, will formalize the name. The most recent example of such recommendations were published in 2012 and for the names and symbols of the elements 114 and 116; See PAC 2012, Vol. 84, No. 7, pp. 1669-1672; http://dx.doi.org/10.1351/PAC-REC-11-12-03
A short review of the current procedures is published in a recent feature by John Corish; See CI 2016, Vol. 38, No. 2, pp. 9-11; http://dx.doi.org/10.1515/ci-2016-0205
On 8 June 2016, IUPAC released the provisional names for the latest 4 elements 113, 115, 117, and 118 – see release and on 28 November 2016, IUPAC announced the approved names and symbols – see release.
For a reflection on the 2016 experience of the naming of elements, see Chem Int Apr 2017, pp. 30-21, by Jan Reedijk; https://doi.org/10.1515/ci-2017-0222
- How to name a new element
Here again, IUPAC has a set of guidelines that outline what sort of name an element can bear. Both the root and the ending must be consistent with the agreed recommendations. The detailed recommendations were published in 2002 and a revision published in 2016 to better accommodate element in group 17 and 18. See PAC 2002, Vol. 74, No. 5, pp. 787-791; http://dx.doi.org/10.1351/pac200274050787 and PAC 2016, Vol. 88, No. 4, pp. 401–405 http://dx.doi.org/10.1515/pac-2015-0802 (or http://www.iupac.org/project/2015-031-1-200)
- Group 1-18 and collective names
Since 1988, IUPAC recommended that the groups (i.e. columns) be simply numbered from 1 to 18. (PAC 1988, Vol. 60, No. 3, pp 431-436; http://dx.doi.org/10.1351/pac198860030431)
Lanthanoids and actinoids are collective names also recommended by IUPAC. Lanthanoids (La to Lu) is preferred over lanthanide, and although lanthanoid means ‘like lanthanum’ and so should not include lanthanum, lanthanum has become included by common usage, however. Actinoids include Ac to Lr.
- Group 3
The question of precisely which elements should be placed in group 3 has been debated from time to time. An IUPAC project has been recently initiated to resolve the question. Will group 3 consist of Sc, Y, Lu, and Lr or, will it consist of Sc, Y, La and Ac?
- Standard atomic weights
One of the tasks of the Commission on the Isotopic Abundances and Atomic Weights (CIAAW) is to periodically review atomic-weight determinations. The most recent report “Atomic weights of the elements 2013” has been published in PAC in March 2016 (PAC 2016, Vol. 88, No. 3, pp. 265–291; http://dx.doi.org/10.1515/pac-2015-0305). In recent years, such systematic review has been released every two years.
The Commission was established in 1899 (yes, in eighteen ninety nine) and is now operating under the Inorganic Chemistry Division of IUPAC. (see www.ciaaw.org ) It also reviews regularly Isotopic compositions of the elements; the latest compilation is also published in PAC in March 2016 (PAC 2016, Vol. 88, No. 3, pp. 293–306; http://dx.doi.org/10.1515/pac-2015-0503)
Yours to use
While IUPAC has no recommendation for a specific form of the periodic table, i.e. 18-column or 32-column format, the version here presented is in the conventional long form and is yours to use.