Latest Extension of the periodic table beyond the seventh period Stories
Modern-day scientific Magellans and Columbusâ€™s, exploring the uncharted seas at the fringes of the Periodic Table of the Elements, have landed on one long-sought island â€” the fabled Island of Stability, home of a new genre of superheavy chemical elements sought for more than three decades.
Actinium is a radioactive chemical element. The symbol for Actinium is Ac and the atomic number is 89. Actinium was discovered in 1899 by French chemist AndrÃ©-Louis Debierne. It was the first non-primordial radioactive element to be isolated. Actinium is amongst a group of 15 similar elements within the periodic table that make up the actinoid series. This substance was also independently discovered by Friedrich Oskar Giesel in 1902 and named it emanium in 1904. In 1904 he named it...
- The abrogation of a law by a higher authority; annulment.
- In music, during the eighteenth century, a song or an instrumental piece similar to the serenade, intended for performance in the open air.