Periodic Table

choi

Peter Pesic, Piecing Together the Periodic Puzzle. The periodic table devised in 1913 revealed ‘gap’ where certain elements ought to be. Scientists set off searching for these rarest of substances. Wall Street Journal, Sept 21, 2013
http://online.wsj.com/article/SB ... 80091414117774.html
(book review on Eric Scerri, A Tale of Seven Elements. Oxford University Press, 2013)

My comment:
(a) Read only the first 2 ½ paragraphs.
(b) “the famous [periodic] table independently introduced in that decade by Dmitri Mendeleev and Julius Lothar Meyer”
(i) Dmitri Mendeleev

(1834-1907; Russian
(ii) Julius Lothar von Meyer (1830-1895) was a German chemist. “Mendeleev published his periodic table of all known elements (and predicted several new elements to complete the table, plus some corrected atomic weights) in 1869. Working completely independently, a few months later, Meyer published a revised and expanded version of his 1864 table, virtually identical to that published by Mendeleev.”  Wiki
(c) The seven precited elements are "technetium [Tc: atomic number 43], promethium [Pm: 61], hafnium [Hf: 72], rhenium [Re:75], astatine [At: 85], francium [Fr: 87; discovered by Marguerite Perey in France (from which the element takes its name) in 1939] and protactinium [Pa: 91]."