235U and 238U are both listed as stable. They are actually slightly radioactive. 238U has t1/2 = 4.5x10⁹ years, 235U has t¹/² = 703.8x10⁶ years, This can be compared to Earth’s age of about 4.6x10⁹ years.
Calculate the decay rate of 238U and 235U in SI;