Alpha Decay: Heavy Nuclei Shedding Particles

Alpha decay happens when heavy nuclei eject an alpha particle.
An alpha particle is two protons and two neutrons—basically a helium nucleus.
This process lowers the atom’s atomic number by 2 and mass number by 4.
Alpha decay is common in heavy elements like uranium, radium, and thorium.
It reduces nuclear size and helps unstable atoms move toward stability.
Alpha particles are relatively heavy and slow compared to other radiation.
A sheet of paper or even skin can block alpha particles.
Inside the body, alpha radiation can be extremely damaging to cells.
Alpha decay provides heat that keeps Earth’s interior warm over billions of years.
The discovery of alpha decay helped reveal the structure of the atom.