What are the two forms of natural radioactive decay resultling in transmutations? Describe the processes.
Alpha and beta decay.
In alpha decay, nucleus emits an alpha particle consnisting of two protons and tow neutrons, so reduces mass by 4 and atomic number by 2. (e.g. alpha decay of uranium-238 to form thorium-234 and a helium nucleus)
In betay decay, a neutron decays into a proton which remains in the nucleus, raising the atomic number by 1, an emitted electron or beta-particle, and an antineutrino. As an antineutrino is emitted, this form of beta decay is known as beta-minus.