EARTH 221 Final Exam
Spectral analysis determine solar system abundances using absorption wavelengths from sun
Carbonaceous chondrite meteorites small spheres of crystals and glass in a silicate-metal-sulfide mix that are assumed
to be primitive material left over from solar system formation that give average
composition of solar system better than spectral analysis
Helioseismic data measure of sunquakes formed by sound waves in sun, used for determining
element abundance in solar system since quake waves change depending on
material they pass through, better estimate than meteorite abundances
Standard atomic mass average of all isotopes, the mass of protons plus neutrons
Isotopes elements with same number of protons but different mass number and number of
neutrons
Isobars elements with same mass number but different amount of protons and neutrons
Isotones elements with same number of neutrons but different mass number and number of
protons
Radiogenic isotopes daughter product of radioactive parent, that can be radioactive or not
% of stable isotopes > 90%
% of radioactive isotopes < 10%
Nuclear reactions reactions involving change in nucleus, occur spontaneously when nuclei are
unstable, and require very high energy input for stable nuclei
Nuclear fission nucleus sheds particles and gets smaller - > larger element into smaller elements
Nuclear fusion combining nuclei into bigger nuclei, not yet producible on large scale
Particle capture, then Nuclear Fission nucleus captures a particle (n or p) becoming unstable and must shed particles and
get smaller
Last stable element 56Fe, acts as boundary between fusion and fission
, EARTH 221 Final Exam
Alpha decay reaction releases 2 protons and 2 neutrons (or a 4He atom) only occurs in heavier elements
(A > 100)
Beta positron decay releases beta positron, when there are too many protons convert to neutron (proton
→ neutron) same mass number
Beta negatron decay releases beta negatron, when there are too many neutrons convert to proton
(neutron → proton) same mass number
Electron capture reaction an electron is captured, proton + e- → neutron (same mass number) no release of
major particle
Gamma reaction high energy electrons are released after being in excited state, often released with
other radiation, no change in mass.
How does N:Z ratio change in heavier isotopes N > Z because of electrostatic repulsion and packing, must have more neutrons in
heavier elements
Nucleosynthesis the process of creating new atomic nuclei
Big Bang nucleosynthesis origin of the universe, main source of H and He in universe
Stellar nucleosynthesis a star's life, nuclear fusion of H to He, bigger stars can burn up to Si, eventually will
run out of gases to burn and die
Death of smaller stars small stars become planetary nebulas
Death of larger stars large stars die and become supernovas
Explosive nucleosynthesis a star's death
Galactic nucleosynthesis cosmic rays in space
2 mechanisms of hydrogen burning proton-proton chain and CNO cycle
Proton-proton chain hydrogen burning in all first generation stars and smaller stars, 3 stage process with
hydrogen to produce a He and more hydrogen to re-start cycle
, EARTH 221 Final Exam
Which elements are our sun producing only H and He
CNO cycle 6 step H-burning process in which carbon allows H to be burned faster, 14C and
4He are the major products of this process. Only happens in larger stars if carbon is
present, which is only found in 2nd generation of older stars
∆m value in E = ∆m x 931.5 atomic mass of products - atomic mass of reactants, can also be mass defect in
formation reactions
Mass defect the difference in amu between the theoretical mass (masses of p and n) and the
measured mass, measured mass is always less than the theoretical mass
Binding energy the energy required to separate a nucleus or the energy releases when the
nucleons bind to form the nucleus, can be calculated with E MeV formula
He burning after most of H is burned in the core, the star contracts due to gravity and then
starts burning He in shell around C-O core, with H burning in outer shell
Triple-α process 3 step reaction process that consumes 3 4He to produce 12C and energy, this 12C
can then be used in CNO cycle
Small stars and triple-α process when 12C becomes available from triple-α process 12C can react with 4He to
produce O, smaller stars stop nucleosynthesis here and eventually explode into
planetary nebulas forming CNO but cannot burn them, with 16O as major product
Large star burning layers Fe, Ni core, Si burning, O burning, Ne burning, C burning, He burning, H burning
with elements created remaining there until T and P conditions are right for burning.
Carbon burning in larger stars 2 step reaction, 12C is burned to produce 20Ne
Neon-burning in larger starts 2 possible reactions, 20Ne photo-disintegrates after hit with photon to produce 16O,
or 20Ne reacts with α to produce 24Mg
Oxygen-burning in larger stars 2 possible 2 step reactions, 16O burned to produce 32S, 32S burned to produce
28Si or α-particle capture to produce 36Ar and 40Ca
Silicon burning final stage of life for larger stars, involves photodisintegration of some 28Si and
other nuclei where α is added to other nuclei up until 56Fe
Why is 56Fe fusion endpoint the most thermodynamically favorable element, with highest binding energy per
nucleon
3 synthesis pathways for heavier elements s-process, r-process, p-process
Spectral analysis determine solar system abundances using absorption wavelengths from sun
Carbonaceous chondrite meteorites small spheres of crystals and glass in a silicate-metal-sulfide mix that are assumed
to be primitive material left over from solar system formation that give average
composition of solar system better than spectral analysis
Helioseismic data measure of sunquakes formed by sound waves in sun, used for determining
element abundance in solar system since quake waves change depending on
material they pass through, better estimate than meteorite abundances
Standard atomic mass average of all isotopes, the mass of protons plus neutrons
Isotopes elements with same number of protons but different mass number and number of
neutrons
Isobars elements with same mass number but different amount of protons and neutrons
Isotones elements with same number of neutrons but different mass number and number of
protons
Radiogenic isotopes daughter product of radioactive parent, that can be radioactive or not
% of stable isotopes > 90%
% of radioactive isotopes < 10%
Nuclear reactions reactions involving change in nucleus, occur spontaneously when nuclei are
unstable, and require very high energy input for stable nuclei
Nuclear fission nucleus sheds particles and gets smaller - > larger element into smaller elements
Nuclear fusion combining nuclei into bigger nuclei, not yet producible on large scale
Particle capture, then Nuclear Fission nucleus captures a particle (n or p) becoming unstable and must shed particles and
get smaller
Last stable element 56Fe, acts as boundary between fusion and fission
, EARTH 221 Final Exam
Alpha decay reaction releases 2 protons and 2 neutrons (or a 4He atom) only occurs in heavier elements
(A > 100)
Beta positron decay releases beta positron, when there are too many protons convert to neutron (proton
→ neutron) same mass number
Beta negatron decay releases beta negatron, when there are too many neutrons convert to proton
(neutron → proton) same mass number
Electron capture reaction an electron is captured, proton + e- → neutron (same mass number) no release of
major particle
Gamma reaction high energy electrons are released after being in excited state, often released with
other radiation, no change in mass.
How does N:Z ratio change in heavier isotopes N > Z because of electrostatic repulsion and packing, must have more neutrons in
heavier elements
Nucleosynthesis the process of creating new atomic nuclei
Big Bang nucleosynthesis origin of the universe, main source of H and He in universe
Stellar nucleosynthesis a star's life, nuclear fusion of H to He, bigger stars can burn up to Si, eventually will
run out of gases to burn and die
Death of smaller stars small stars become planetary nebulas
Death of larger stars large stars die and become supernovas
Explosive nucleosynthesis a star's death
Galactic nucleosynthesis cosmic rays in space
2 mechanisms of hydrogen burning proton-proton chain and CNO cycle
Proton-proton chain hydrogen burning in all first generation stars and smaller stars, 3 stage process with
hydrogen to produce a He and more hydrogen to re-start cycle
, EARTH 221 Final Exam
Which elements are our sun producing only H and He
CNO cycle 6 step H-burning process in which carbon allows H to be burned faster, 14C and
4He are the major products of this process. Only happens in larger stars if carbon is
present, which is only found in 2nd generation of older stars
∆m value in E = ∆m x 931.5 atomic mass of products - atomic mass of reactants, can also be mass defect in
formation reactions
Mass defect the difference in amu between the theoretical mass (masses of p and n) and the
measured mass, measured mass is always less than the theoretical mass
Binding energy the energy required to separate a nucleus or the energy releases when the
nucleons bind to form the nucleus, can be calculated with E MeV formula
He burning after most of H is burned in the core, the star contracts due to gravity and then
starts burning He in shell around C-O core, with H burning in outer shell
Triple-α process 3 step reaction process that consumes 3 4He to produce 12C and energy, this 12C
can then be used in CNO cycle
Small stars and triple-α process when 12C becomes available from triple-α process 12C can react with 4He to
produce O, smaller stars stop nucleosynthesis here and eventually explode into
planetary nebulas forming CNO but cannot burn them, with 16O as major product
Large star burning layers Fe, Ni core, Si burning, O burning, Ne burning, C burning, He burning, H burning
with elements created remaining there until T and P conditions are right for burning.
Carbon burning in larger stars 2 step reaction, 12C is burned to produce 20Ne
Neon-burning in larger starts 2 possible reactions, 20Ne photo-disintegrates after hit with photon to produce 16O,
or 20Ne reacts with α to produce 24Mg
Oxygen-burning in larger stars 2 possible 2 step reactions, 16O burned to produce 32S, 32S burned to produce
28Si or α-particle capture to produce 36Ar and 40Ca
Silicon burning final stage of life for larger stars, involves photodisintegration of some 28Si and
other nuclei where α is added to other nuclei up until 56Fe
Why is 56Fe fusion endpoint the most thermodynamically favorable element, with highest binding energy per
nucleon
3 synthesis pathways for heavier elements s-process, r-process, p-process
