Answer: phosphorus --(see attached photo for reaction)
Explanation: atoms with unstable nucleus undergoes radioactivity and they change to other atoms as they decay.
There are three types of radiation emitted from radioactive atoms.there is
The alpha ,beta and gamma emission. The alpha emission is deflected towards a negative plate and the beta is deflected towards a positive plate, when they are passed through an electric field.
In Alpha emmision , the new atom produced has it's mass number less than it's original atom by 4 and it's atomic number less by 2. The particles emitted during an alpha emission is identified as the helium nucleus.
In beta emission, a negative particle called negatron or a positive particle called positron is emited.