NUCLEAR DECAY

ISOTOPES

Isotopes elements that have th same number of protons (same Z) but different atomic weights (A). The stability o an isotope depends on the relative number of neutrons and protons in the nucleus.
1.2 is the most stable ratio
1.5 the ratio rises for heavy elements
Isotopes whose ratios deviate are unstable,spontaneous decay equals radioactive.
Isotopes with even numbers of protons and even neutrons are the most stable and isotopes with an odd number of protons and odd number of neutrons are least stable.All isotopes heavier than 209 Bi are unstable.NUCLEAR FORCES HOLD THE NUCLEUS TOGETHER.
 Most nuclei have a binding energy of about 8 MeV per nucleon (i.e Carbon 12 has a binding energy of about 8x12 = 96MeV)

TYPES OF DECAY

ALPHA DECAY
BETA DECAY
GAMMA DECAY
ISOMERIC TRANSITIONS
INTERNAL TRANSITIONS
POSITRON DECAY
ELECTRON DECAY

ALPHA DECAY

During alpha particle decay a alpha particle (NUCLEUS OF HELIUM)  is emitted.An alpha particle has an atomic number of 2 and an atomic weight of 4. The decay of 226 Ra is an example of alpha decay. Alpha decay occurs when the parent nucleus has to many positive charges.

                                                                                       Z decreases by 2
                       ALPHA DECAY                                     A decreases by 4