Flashcards
Radioactivity
Cards in this deck (51)
- 1Transmutationatoms being converted to atoms of another element
- 2Nuclideparticular nucleus (specific composition) *each isotope of an element has a different nuclide*
- 3Notation for neutron1
N
0 - 4Notation for proton1
P
1 - 5Notation for an electron0
e
-1 - 6Radioactive Decaywhen a nuclide is unstable and spontaneously emits radiation
- 7What does NOT affect the intensity of radiation?temperature, pressure, or other physical and chemical conditions
- 8Alpha Particlesα
- 9Beta Particleshigh-speed electrons; β
- 10Gamma raysvery high-energy photons; γ
- 11What happens when a nuclide decays?forms a daughter nuclide of lower energy
- 12Alpha decayloss of an α particle from the nucleus; A decreases by 4 and Z decreases by 2 in the daughter nuclide
- 13Beta decayejection of a β- particle from the nucleus; a neutron is converted to a proton and a β- particle is expelled; Z increases by 1 unit
- 14Positron emissionβ+ particle is emitted from the nucleus; proton is converted to a neutron and a positron is emitted; Z decreases by 1 unit
- 15Positronthe antiparticle of the electron
- 16Electron captureoccurs when the nucleus interacts with an electron in a low atomic energy level; proton is transformed into a neutron
- 17Gamma emissionthe radiation of high-energy Y photons; usually occurs together with other forms of radioactive decay; different Y photons of different energies can be emitted as the nucleus returns to group state
- 18What two factors determine the stability of a nuclide?1. the number of neutrons (N), the number of protons (Z), and their ratio (N/Z)
2. the total mass of the nuclide - 19Band of stabilityproduced by a plot of numbers of neutrons vs. number of protons for all stable nuclides
- 20As Z increases, the N/Z for a stable nuclei gradually _________.increases
- 21All nuclides with Z > ___ are unstable83
- 22If the N/Z ratio is too HIGH...neutrons are converted to protons via beta decay
- 23If the N/Z ratio is too LOW...protons are converted to neutrons via positron emission or electron capture
- 24Electrostatic Repulsive Forcesprotons experience these forces within the nucleus which destabilize the nucleus
- 25Strong Forceexists between all nucleons, contracts the weaker repulsive forces
- 26What leads to greater stability?the pairing of spins between nucleons
- 27Elements with an _____ number of protons (Z) have a larger number of stable nuclideseven
- 28Nuclide type: neutron-rich Description: high N/Z Mode of Decay: β- decay (lowers N/Z)..
- 29Nuclide type: proton-rich Description: low N/Z Mode of Decay: β+ emission or e- capture (increases N/Z).
- 30Nuclide Type: heavy nuclides Description: Z > 83 Mode of Decay: α decay (reduces both Z & N.
- 31Decay Serieswhen all of the radioactive nuclides that are produced one after the other until a stable nuclide is made
- 32What are three ways to detect radioactivity?1. can expose light-protected films
2. can ionize the air
3. give off flash of light when interacting with specific chemicals - 331 Ci (curie) = 3.70e10 d/smeasures radioactivity
- 34The rate of radioactive decay (activity-A) is proportional to the ________.number of nuclei present (N)
A=kN - 35Radioactive decay follows ________first-order kinetics
- 36rate constant = ___________decay constant (k)
- 37The larger the k value, the _________ the activity of the substancehigher
- 38Half-Lifethe time taken for half the nuclei in a sample to decay
ln(Nt/N0)=-kt Nt=N0e-kt ln(N0/Nt)=kt - 39Half-Life of 14Ct1/2=ln2/k
- 40Radioisotopescan be used to determine the ages of certain objects
- 41Radiocarbon Datingmeasures the relative amounts of 14C and 12C in materials of biological origin
- 42The mass of the nucleus is less than....the combined masses of the nucleons
- 43Mass always __________ when nucleons form a nucleuslost (the lost mass is released as energy)
- 44Nuclear Binding Energyenergy required to break 1 mol of nuclei into individual nucleons
- 45Electron Volt (eV)way to express binding energy
- 46nucleus + nuclear binding energy --> nucleons,
- 471 amu = 931.5e6 eV = 931.5 MeV.
- 48The binding energy/nucleon peaks at elements with a mass number ________.A = 60
(nuclides become more stable with increasing number up to around 60 nucleons, after which stability decreases) - 49Nuclear Fission- heavier nucleus splits into lighter ones using neutron bombardment to start the process
-releases energy and generates more high-energy neutrons, which causes further fission to occur
-the fission process becomes self-sustaining by a chain reaction - 50Nuclear Fusion-lighter nuclei can combine to form a heavier nucleus
-requires high energy input to initiate the process
- - 51Critical Massmass required to achieve a self-sustaining chain reaction
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- Final Chemistry Flashcards on Radioactivity, created by alison_whiteman on 01/12/2015.
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