1. Two short-lived isotopes of element are produced in a nuclear reaction. One of these isotopes has a mass of 5.3731 amu and accounts for 85.5% of the production. The remaining other isotope has a mass of 7.3904 amu. Use this information to calculate the atomic mass of this element.
2. A specific radioactive isotope has a half-life of 24.2 minutes. How long will it take this isotope to decay to 1/8 of its original amount?
3. The formula of the ionic compound that forms two ions,A^2+ and R^9-, Can be written as AxRy. What is the value for X?