The official atomic weights of 19 elements have just been changed

Time to update all your periodic tables.

In their ongoing effort to keep things as mind-numbingly precise as possible, The International Union of Applied Chemistry (IUPAC) and the U.S. Geological Survey announced yesterday that the atomic weights of 19 elements have been officially and oh-so-incrementally changed.

Via USGS:

The standard atomic weights of molybdenum, cadmium, selenium, and thorium have been changed based on recent determinations of terrestrial isotopic abundances. In addition, the standard atomic weights of 15 elements have been revised based on a new assessment of their atomic masses by the International Union of Pure and Applied Physics.

Changes in standard atomic weights:

molybdenum: from 95.96(2) to 95.95(1)
cadmium: from 112.411(8) to 112.414(4)
selenium: from 78.96(3) to 78.971(8)
thorium: from 232.038 06(2) to 232.0377(4)

beryllium: from 9.012 182(3) to 9.012 1831(5)
fluorine: from 18.998 4032(5) to 18.998 403 163(6)
aluminium (aluminum): from 26.981 5386(8) to 26.981 5385(7)
phosphorus: from 30.973 762(2) to 30.973 761 998(5)
scandium: from 44.955 912(6) to 44.955 908(5)
manganese: from 54.938 045(5) to 54.938 044(3)
cobalt: from 58.933 195(5) to 58.933 194(4)
arsenic: from 74.921 60(2) to 74.921 595(6)
yttrium: from 88.905 85(2) to 88.905 84(2)
niobium: from 92.906 38(2) to 92.906 37(2)
caesium (cesium): from 132.905 4519(2) to 132.905 451 96(6)
praseodymium: from 140.907 65(2) to 140.907 66(2)
holmium: from 164.930 32(2) to 164.930 33(2)
thulium: from 168.934 21(2) to 168.934 22(2)
gold: from 196.966 569(4) to 196.966 569(5)

According to IUPAC, the changes to the standard atomic weights will be published in a brand spanking new Table of Standard Atomic Weights, to be published in Pure and Applied Chemistry in 2014. If you can't wait that long, and need to know the accurate weight of these elements to the sixth, seventh, or even – you crazy, reckless bastardeighth decimal place, the revised values for atomic weights can be found online in the Table of Standard Atomic Weights (xls) at the website of the Commission on Isotopic Abundances and Atomic Weights.