Quantum Number and Nuclear Physics (5/13)

Electromagnetic Gravitational Strong nuclear Weak nuclear

Holds protons together in the nucleus (stronger than electromagnetic force)

lower energy more stable

The different of 0.047 x 10^-27 kg of the expected vs actual mass of nucleus

Explains why the mass of the nucleus has a smaller mass combined than the total mass of each individual particle added together

E=mc^2 speed of light is squared measured in eV (electron volts) m=E/c^2

a property of all matter wavelength= h/ mass*velocity 6.62x10^-34 is h

says why electrons do not crash into the nucleus due to the attractive force between opposite charges -electron must be in constant motion

when photons hit surface of metal, they excite metallic electrons to higher energy states causing them to move further

E_kinetic=h*f-phi phi- energy going in

corresponds to number of photons

E_photon=KE_electron + Work function

atoms with the same number of protons, but different number of neutrons

involving nuclear reactions like fusion, fission, nuclear decay, transmutation

two or more nuclei forced together with very high energy levels Releases binding energy A large amount of energy is used to force two or more nuclei together, leading to the formation of a different element

Breaks large nucleus into more nuclei (no particles are lost) Energy can be harvested by nuclear power plant

When unstable isotopes break down and eject mass, and energy or photons

Emission of alpha particle which is two protons and two neutrons (also known as helium nucleus) -decreases by atomic number of 2 and mass of 4

-: neutron is converted to a proton and an electron is ejected atomic number goes up by one, but mass does not change +: proton is converted into a neutron and a positron is ejected atomic number goes up by one, but mass does not change atomic number goes down by one, but mass does not change

a nucleus absorbs electron and merges with proton to become an electron causes atomic number to decrease by one and weight stays same

excited nucleus, high in energy no mass or charge so no change in either just change in energy

nuclear particles are never lose entirely subtract particles bring lost from parent nucleus Atomic mass and atomic number are unaffected by gamma

Amount of time for half of the material to decay

N=N0(1/2)^t/t_1/2