Isobars are atoms that have same atomic mass but different atomic number. They have different atomic numbers because they have different numbers of protons. They have the same atomic mass because they have just enough neutrons to make the same total of nucleons. Isobars occur at different places in the Periodic Table.
The Holocaust (also called Ha-Shoah in Hebrew) refers to the period from January 30, 1933 - when Adolf Hitler became chancellor of Germany - to May 8, 1945, when the war in Europe officially ended.
When Did the Holocaust Start?  Some years ago, a leading Holocaust historian, Deborah Dwork spoke at a memorial to Crystal Night in British Columbia, the night in November 1938 when Nazi mobs, inspired by the murder of a German foreign official by a Polish Jew, destroyed hundreds of Jewish stores and shops.