Atomic Structure Flashcards
What is specific ionization
The number of ion-pairs formed per centimeter traveled in a given material
Ionization that occurs by removing electrons as it passes by atoms which eventually slows the particle down describes what kind of particle
Alpha particle
The following is a description of what kind of decay:
Non-stable nuclei that emit a neutron
Neutron emission
Removing an electron from orbit is called
Ionization
Define Radioactive decay constant
The probability per unit tie that an atom of a specific nuclide will decay
What is the charge of an electron
Negative (-1)
Define Curie
A measure of radioactive decay equal to the number of disintegrations that one gram of radium-226 undergoes in one second (3.7E10 dps)
The following is a description of what kind of decay:
A nuclei having excess protons that captures an inner orbit electron
Electron capture
What is the approximate atomic mass (in amu) of a proton
~ 1 amu
Uranium with an isotope concentration less than its natural value
Depleted uranium
Electromagnetic radiation similar to an x-ray that has no mass and no charge. Attenuated by photo-electric effect, Compton scattering, and pair-production
Gamma emission
Define nuclide
Atoms containing a unique combination of protons and neutrons
Describe the principle of conservation of mass and energy
The sum of mass plus the sum of energy cannot change
What is the charge of a neutron
Neutral
Ionization that occurs from collisions with orbiting electrons which eventually slows the particle down describes what kind of particle
Beta particle
Define isotope
Atoms of the same element with the same number of protons but different number of neutrons
Describe the principle of conservation of momentum
Momentum cannot be created or destroyed
A stable nuclide in the Chart of the Nuclides is what color
Gray
Nuclides in the upper right corner of the line of stability undergo what type of decay
Alpha decay
Define activity
Rate of decay of a sample
Define mass defect
The difference between the mass of an atom and the sum of masses of its parts (protons, neutrons, and electrons)
Where are neutrons located
In the nucleus
Uranium with an isotope concentration greater than its natural value
Enriched uranium
Gamma emission can be shielded by:
- Several feet of concrete or water
- A few inches of lead
Where are electrons located
Orbiting around the nucleus
Define atomic weight
The average weight of all isotopes of an element
A strong attractive force between all nucleons
Nuclear Force
Nuclides above and to the left of the line of stability undergo what type of decay
Beta-plus
A weak attractive force that acts between all nucleons
Gravitational Force
Define binding energy
Amount of energy that must be supplied to a nucleus to completely separate its nuclear particles (equals the mass defect)
Nuclides below and to the right of the line of stability undergo what type of decay
Beta-minus
An alpha particle can be shielded by:
- Centimeters of air
- A sheet of paper
What is the charge of a proton
Positive (+1)
Define atom percent
The percentage of atoms of an element that are of a particular isotope
Where are protons located
In the nucleus
Neutron emission can be shielded by:
12 inches of water
Decay that moves down one and to the right one on the Chart of Nuclides is
Beta-plus
A {blank} ray comes from the nucleus
Gamma Ray
Define radioactivity
The spontaneous emission of particles or gamma radiation
Define weight percent
Percentage weight of an element that is a particular isotope
What is the conversion between half-life and decay constant
Decay Constant = 0.693/half-life
What is radioactive equilibrium
When the decay and production rates of a nuclide are equal
What is secular radioactive equilibrium
When a parent has an extremely long half-life each descendant builds to an equilibrium with decay rates equal to the original parent
Describe the principle of conservation of charge
Charge cannot be created or destroyed.
Define mass number
The number of protons plus the number of neutrons in a nucleus
The following is a description of what kind of decay:
A neutron is converted to a proton increasing the number of protons but leaving the mass unchanged
Beta-minus decay
The following is a description of what kind of decay:
When gamma interacts with an electron moving it outward from the nucleus but eventually moves back to its original orbit emitting x-ray
Internal conversions
The following is a description of what kind of decay:
A proton is converted to a neutron leaving the mass unchanged
Beta-plus decay (positron)
The following is a description of what kind of decay:
An unstable nucleus ejects a particle containing 2 protons and 2 neutrons.
Alpha decay
What is the approximate atomic mass (in amu) of a neutron
~ 1 amu
A {blank} ray comes from electrons
X-Ray
Define Becquerel
The SI unit of radioactive decay equal to 1 dps
Define atomic number
The number of protons in a nucleus
What is the difference between charged and uncharged particles with regards to ionization
- Charged particles directly ionize.
- Uncharged particles only cause ionization indirectly
Decay that drops two spots and moves to the left two spots on the Chart of Nuclides is
Alpha decay
Decay that moves up one and to the left one on the Chart of Nuclides is
Beta-minus
Define radioactive half-life
The amount of time for activity to decrease to one half of its original value
Describe how the neutron to proton ratio affects an nuclides stability
The line of stability (ratio of neutrons to protons) increases nearly linearly as you increase AMU
A strong repulsive force between like charged particles
Electrostatic Force
A short lived and quickly attenuated particle due to interactions with negatively charged electrons is a
Positron
The following is a description of what kind of decay:
A nucleus in an excited state attempts to reach a ground state. Usually occurs after a particle emission.
Isomeric transition
The following is a description of what kind of decay:
High energy radiation from the nucleus resulting in the nuclide reaching the ground state
Gamma ray emission
Describe neutrinos
The amount of energy that is lost during decay that ensures the conservation of energy and momentum
A beta particle can be shielded by:
Thin sheet of metal
What is the approximate atomic mass (in amu) of an electron
~ 1/1835 amu
An unstable nuclide in the Chart of the Nuclides is what color
Any color other than Gray
Attenuated by elastic scatter, inelastic scatter, and absorption
Neutron emission
The amount of energy that results from the conversion of 1 amu to energy
931.5 MeV
Describe the principle of conservation of mass number
In a reaction there cannot be a net change in the number of nucleons
