Applications of radioisotopes in various fields including food security

Science fraternity across the world is celebrating 2019 as the ^International Year of the Periodic Table of Chemical Elements which was discovered by the Russian scientist, Dmitri Mendeleev in 1869. Each element has a unique position in the periodic-table as per their atomic number and correlated to their chemical reactivity. Isotopes of an element have same atomic number but differ in mass number. So, they are placed at the same position in the periodic table and have similar chemical behaviour. A handful of elements (19 nos) are present as monoisotopic in nature. Rest are present in several isotopic forms with varying natural abundances. Transuranic elements beyond atomic number of 94 do not found in nature. Although listed in the periodic table, four elements, technetium, promethium, astatine. and francium although having lower atomic number than U (at no. 92) virtually do not exist in nature