What is Mendeleev's predicted elements?
In 1869, Professor [[Dmitri Mendeleev]] created the first [[periodic table]] of [[chemical elements]]. He arranged the elements from the lightest one to the heaviest one.<ref>{{cite journal|last=Kaji|first=Masanori|title=D.I.Mendeleev's concept of chemical elements and ''The Principles of Chemistry''|journal=Bulletin for the History of Chemistry|volume=27|pages=4–16|year=2002|url=http://www.scs.uiuc.edu/~mainzv/HIST/awards/OPA%20Papers/2005-Kaji.pdf|access-date=2013-03-12|archive-date=2008-12-17|archive-url=https://web.archive.org/web/20081217080509/http://www.scs.uiuc.edu/~mainzv/HIST/awards/OPA%20Papers/2005-Kaji.pdf|url-status=dead}}</ref> When he proposed his periodic table, he placed empty spaces between some elements. He said that the empty spaces were for un[[Discovery (observation)|discovered]] elements. Mendeleev had also predicted the [[Property#Chemistry|properties]]{{Broken anchor|date=2024-12-13|bot=User:Cewbot/log/20201008/configuration|target_link=Property#Chemistry|reason= The anchor (Chemistry) [[Special:Diff/5319590|has been deleted]].}} of these undiscovered elements. ==Naming the undiscovered elements== Mendeleev gave temporary names for the undiscovered elements. He used the [[wikt:prefix|prefixes]] '''eka-''', '''dvi-''' and '''tri-''' and combined it with any known elements in the same [[group (periodic table)|group]] with the undiscovered element. Eka-, dvi- and tri- are numbers 1, 2 and 3 in the [[Sanskrit]] language. The use of the prefix depends on how far the known element is from the unknown element. For example, [[germanium]] was called eka-silicon because [[silicon]] is placed one [[period (periodic table)|row]] above germanium, and [[rhenium]] was called dvi-manganese because [[manganese]] is placed two rows above rhenium. The names of these elements were changed after they were discovered. Other scientists use the eka- prefix, too. Eka- is also used in the names of elements that Mendeleev did not predict. Before [[francium]] was discovered, it was called ''eka-[[caesium]]'', and