Elem Symb S th AW P Determine the number of atoms in a solid square disc of pure Thorium with sides measuring 5.1 cm and a thickness of 1.3 mm. Assume the atomic weight and density of Th are 0.2320381 g/millimole and 15400 kg/cu m, respectively. Apply definitions of density, volume, mole and atomic weight. Thorium Th 5.1 1.3 0.232038 15400.0 + Avogadro's No 6.0221E23 atoms/mole Express algebraic solution in terms of s, th, AW and rho..