actinide element उदाहरण वाक्य

At least two additional, two-letter generic chemical symbols are also in informal usage, " "'Ln "'" for any lanthanide element and " "'An "'" for any actinide element . " "'Rg "'" was formerly used for any rare gas element, but the group of rare gases has now been renamed noble gases and the symbol " "'Rg "'" has now been assigned to the element roentgenium.