In the mid-1800s, the elements of the periodic table were being identified and discovered, yet for many decades element 43, between molybdenum and ruthenium (Fig. Q30.7), remained unfound. Technetium (Tc) was finally discovered almost 100 years later, in 1936. 

(a) Use the Internet to discover what is special about this element, and why it was so hard to find. 

(b) Where can technetium be found today?