Radium-226 decays by alpha emission to radon-222. Suppose that 25.0% of the energy given...

Radium-226 decays by alpha emission to radon-222. Suppose that 25.0% of the energy given off by one gram of radium is converted to electrical energy. What is the minimum mass of lithium that would be needed for the voltaic cell at standard conditions, to produce the same amount of electrical work