Ch+29+-+Radioactivity

__Recap from Chemistry__

Z=Atomic Number (number of protons in nucleus) N= Number of Neutrons in nucleus A= Mass Number (number of nucleons in nucleus=Z+N)

__Physical Properties of Atoms-

Q values-

Alpha decay-__ the nucleus emits an alpha particle, two neutrons and two protons. so N decreases by two Z decreases by two and A decreases by 4. Beta Decay-here an electron or a positron is emited Gamma Decay- here the nucleus is unstable so it spontaniously decays with a gamma emmission __Decay constant and half life__- the nucleus decays with logestic regression and can be represented by the equation N=Noe^-kt where k is the decay constant. No is the initial amount t is time since and N is amount currently present. Half life is simply the time it takes for half of a given number of nuclei to decay. __Nuclear Stability and binding energy-__ The nucleus is a closely packed cluster of protons and neutrons, yet there is a large electrostatic force between protons, the reason the nucleus does not come apart is because of the nuclear force, which is an attractive force between all nuclear particles.in order for the nucleus to be stable the nuclear force must be greater than the coulomb force that is propeling it apart. so as more protons are added the coulomb force increases and it s less stable. the binding energy is the difference of the total energy of the combined system( the nucleus found in appendix b) and and combined energy of the seperated nucleons (protons and neutrons summed together), it is the energy that must be added to the nucleus to break it apart.