Algodoo

Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. In other words, the time it takes for half of a substance to decay into something else, here the atom loses 2 electrons, it does not decay, it simply ionizes (AKA it loses one or more electrons)