(a) Give the name and symbol of another element that does not have stable isotopes. Explain why you chose that element.
(b) Even though the periodic table lists a whole number for ⁹⁸Tc, we do know the isotope's precise mass. Find ⁹⁸Tc on pTable.com and get precise mass and "half life" of this isotope.
(c) Flash back to periodic table information, definition of amu, and significant figures. In question (b) you found the "precise" mass of an isotope. Why didn't we say "exact mass"? Is there any isotope with an "exact" mass?