Nuclear Chemistry

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protons/neutrons in atomic nuclei/nuclide
atom identified by what is in the nucleus (protons/neutrons)
mass defect
difference between the mass of an atom and the sum of the masses of its particles.
nuclear binding energy
energy released when a nucleus is formed from nucleons-causes mass defect. amount of energy needed to break apart a nucleus
band of stability
stable nuclei cluster over a range of neutron/proton ratio. most stable ratio nuclei = 1:1
nuclear reaction
a reaction that affects the nucleus of an atom
a change in the identity of a nucleus as a result of a change in its number of protons
radioactive decay
spontaneous disintegration of a nucleus into a lighter nucleus accompanied by emission of particles
nuclear radiation
particles of electromagnetic radiation emitted from nucleus during radioactive decay
electron capture
an inner orbital electron is captured by the nucleus of its own atom; inner orbital electron combines with a proton forming a neutron
time required for half the atoms in a radioactive nuclide to decay. more stable nuclides have longer half-lives
decay series
series of radioactive nuclides produced by successful radioactive decay until stable nuclide is reached
artificial transmutation
make artificial radioactive nuclides, bombardment of nuclei with charged and uncharged particles, greater quantities of energy required to penetrate
transuranium elements
elements with more than 92 protons in their nuclei. they are all radioactive
unit used to measure nuclear radiation exposure, equal to gamma and X-ray radiation that produces 2 x 10^9 ion pairs through 1 cm^3 of dry air
unit of measure of dose of ionizing radiation, measure of radiation damage to human tissue
measurements of radiation
film badges or Geiger-muller counters
film badges
the exposure of film needed to measure the approximate radiation exposure of people working with radiation
Gieger-muller Counters
instruments that detect radiation by counting electric pulses carried by gas and ionized by radiation
radioactive dating
process where approximate age of an object is determined based on amount of radioactive nuclides present
nuclear waste
unusable materials with radioactive isotopes. disposed all around the US with no real solution
nucleus of a heavy atom splits and and produces 2 smaller nuclides. releases energy and produces waste
chain reaction
material that starts reaction is on of the products, triggering more reaction
critical mass
minimum amount of nuclides that provide neutrons needed to stop chain reaction
Marie and Pierre Curie (1896)
Determined why uranium exposed film. Discovered that some nuclei are unstable and spontaniously emit radioation.
Mass defect
The amount of mass missing from a Nuclide after the mass of all of the particles is taken into account. (If you add up the mass of each particle in an atom and compare it to the actual mass of the atom, there is a small amount of missing mass-)
Albert Einstein
Explained the mass defect with his equation E=mc^2
Nuclear tug of war
Electrostatic force pulls nuclei apart
Large nuclei tend to be _______
Magic number
The number of nucleons in each full level. Nucleons tend to be paired.
Unstable nuclei ejecting particle either naturally or via bombardment in a particle accelerator.
Nuclear reaction
Reactions involving the nucleus of an atom, as opposed to the electrons of an atom.
During radioactive decay, if the atomic number changes the element changes.
Ionizing radiation
emitted or absorbed by an atom, it can liberate a particle from the atom. Includes: cosmic rays, alpha, beta, gamma rays, x-rays and any charged particle moving at relativistic speed.
Non-ionizing radiation
Any type of radiation that does not carry enough energy per quantum to ionize atoms or molecules. Instead of producing charged ions while passing through matter.
Nuclear Fission
When heavy nuclei split into lighter, more stable nuclei. This occurs in nuclear power plants, as well as in medical applications and radioactive dating.
Nuclear fusion
Light mass nuclei combine to form heavier, more stable nuclei. This occurs in stars like our sun and hydrogen bombs.
Proton (quarks)
Up up down 2/3+2/3-1/3 = 1
Up down down 2/3-1/3-1/3 =0
Weak force
Change in flavor –> w+z bosons this is beta decay
Higgs boson
Electron do interact, photons do not. It is the _____ interacting with electrons that slows them down, giving mass and charge. the photons do not interact with the _______ so no mass and no charge.
Nuclear force
Holds nucleons together
Protons plus neutrons (held together by exchanging pions)
An atom defined by its number of protons and neutrons
Mass Defect
The amount of mass missing from a nuclide after the mass of each particle is taken into account.
Nuclear Binding Energy
The energy formed from the conversion of mass to energy when the nucleus is formed.
Nuclear Reaction
A process in which 2 nuclides collide
Alpha Radiation
When an atom spits out an alpha particle (mass of 4 charge of 2).
Beta Emission
When an atom spits out an electron (mass of 0, charge of -1)
Gamma Radiation
When an atom spits out a photon (mass 0, charge 0)
Positron emission
When an atom spits out a positron (mass of 0, charge of 1)
Electron Capture
Neutron to proton ratio is too small and a positron can’t be released, so it steals a 1s electron to make a proton a neutron.
Radioactive decay where the atomic number (and therefore the atom) changes.
Ionizing Radiation
Radiation that liberates a particle from the atom. IE: cosmic rays, alpha, beta and gamma rays, X-rays etc.
Non-Ionizing Radiation
Any type of electromagnetic radiation that does not carry energy per quantum to ionize atoms of molecules.
The amount of time it takes for half of the atoms in an unstable nuclide to decay.
Nuclear fission
When heavier nuclei split into lighter, more stable nuclei.
Held together by exchanging gluons. One of the two basic constituents of matter. Three of them make up every proton and neutron.
Light particles- truly elementary (ie electron, neutrino, bosons)
Heavy particles (protons and neutrons) made up of smaller particles. Broken down into smaller quarks.
Strong nuclear force
hold nuclei together
Weak nuclear force
Typical field strength is 10-11 times weaker than electromagnetic force and 10-13 times weaker than strong nuclear force. Responsible for positron emission and beta decay.
Higgs field
Responsible for electron mass.
Proton quark configuration
U, U, D
Neutron quark configuration
U, D, D
a subatomic particle that bind quarks together. Responsible for color change.
Keep protons and neutrons together,
Band of stability
The graph of the number of neutron plotted against the number of protons.
Decay series
A series of radioactive nuclides produced by successive radioative decay until a stable nuclide is reached
Unit used to measure the dose of ionizing radiation.
Unit used to measure radiation exposure.
Radioactive dating
The process by which approximate age of an object is determined based on an amount of certain radioactive nuclides present.
Lise Meitner
Australian physicist who first described nuclear fission.
Nuclide (isotope)
An atom identified by its number of protons and neutrons.
Nuclear binding energy
Measure of the stability of a nucleus. Conversion of mass to energy when the nucleus is formed.
Most stable
-> 1:1 1:1.5 1:2.
Radioactive decay
The process of emitting particles and/or energy from nucleus
Hahn and Strassman
Who discovered fission? (And Meitner)
Enrico Fermi
discovered the possibility of emission of secondary neutrons and of a chain reaction. He was one of the leaders of the team of physicist on the Manhattan project for the development of nuclear energy and the atomic bomb.
2/3-1/3-1/3 = 0
2/3-1/3-1/3 =+1
Strong force
Changes color –> gluons, secondary result is pion exchange
Color change in quarks mediated by____.
Gluons (strong nuclear force)
Strong Nuclear force
Holds nucleons together
Categories: Nuclear Chemistry