Potassium-40 undergoes three different modes of radioactive decay (Beta decay, Positron decay, and Electron Capture decay). Write balanced nuclear reactions for each of these decay modes. Are the products stable (not radioactive)?

1 answer

On this forum it isn't easy to write isotopes so I use the first number to show atomic number (protons) and second number to show mass number (protons + neutrons). I'll do the first one for beta decay.
19K40 ==> -1eo + 20Ca40
Note the first number add up on both sides and the second number adds up on both sides.