Nuclear Chemistry

Nuclear Stability Protons and neutrons are attracted by a short range force known as nuclear force Occurs between proton-proton, neutron-neutron, and proton-neutron As more protons are added to nucleus more neutrons must be added to add to the nuclear force and overcome the electrostatic force of the positive protons Smaller elements have a proton to neutron ratio that is 1:1 but as elements get larger the ratio changes to 1:1.5 By element 83, there is too much electrostatic force to have any stable isotopes

Radioactive Decay As the nucleus gets so large that it can’t hold itself together, it begins to break down Nucleus will begin to emit particles to stabilize its forces Three major types: alpha, beta, and gamma

Radioactive Decay Alpha Decay Nucleus emits 2 protons and 2 neutrons Decreases the mass number by 4 and the atomic number by 2 Beta Decay A neutron will become a proton and an electron then emit the electron Shifts the ratio and increases the atomic number by 1

Radioactive Decay Gamma Decay Emission of electromagnetic energy as the nucleus returns to the ground state Usually, follows another type of decay

Half Life Amount of time needed for half of the atoms of a substance to decay C-14 (5715 years) Pu-239 (24100 years) Po-218 (3 mins)

Decay Series Series of decay that a nuclide will produced by successive radioactive decay until a stable atom is reached U-238 will decay into Pb-206 through the following chain A(alpha), B (beta), B, A, A, A, A, A, B, B, A, B, B, A Half Lives will change with the new substances