What happens to a radioisotope when it undergoes nuclear decay?

The radioisotope changes into another element/atom through the process of nuclear decay

Explanation:

Nuclear decay is a process in which an unstable radioisotope changes into another element through the emission of characteristic radiation which are essentially fast moving energetic particles. This could be in the form of alpha, beta or gamma particles.

For example a Uranium, U-238 radioisotope gets converted to Thorium Th-234 nucleus through the release of alpha particles as shown below:

²³⁸U → ²³⁴Th + ⁴He

If the reaction you are considering is:

Mg + 1/2O2 → MgO

The mass of Magnesium metal is the mass from the weighing balance measured at the start of the experiment

Theoretical yield of MgO can be determined based on the reaction stoichiometry. i.e. 1 mole of Mg yields 1 mole of MgO. therefore, from the known moles of Mg (= mass of mg/atomic mass of Mg) the # moles of MgO produced can be calculated.

% yield = (experimental/theoretical)*100