How would you determine the half-life of an unknown element?

To determine the half-life of an unknown element, you would first measure its initial quantity and then monitor the decay over time using a radiation detector. By recording the time it takes for half of the initial amount to decay, you can calculate the half-life. This process often involves plotting the decay data on a graph and finding the point where the quantity reduces to half its original value, allowing for precise determination of the half-life.