A beta-particle is an electron emitted from the nucleus of an atom following the decay of a neutron into a proton. Beta rays are deflected by a magnetic field in a direction that indicates a negative charge, thus they are electromagnetic in nature.
The beta particle released is basically a electron with -1 charge and no mass.
General representation of beta particle in the form of given as
Oxygen and magnesium come together in a chemical reaction to form this compound. After it burns, it forms a white powder of the magnesium oxide. Magnesium gives up two electrons to oxygen atoms to form this powdery product. This is an exothermic reaction.