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18 Cards in this Set
- Front
- Back
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Radioactive decay: Alpha particles |
___________ particles(type of radioactive decay) may be emitted from the nucleus. It is composed of 2 protons and 2 neutrons, thus emission means the mass number of the isotope is reduced by 4 and the atomic number by 2 Ch. 9 |
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Radioactive decay: Beta particle |
Type of radioactive decay in which a ____________ or electron is given off from a nucleus. Mass number remains unchanged and the atomic number increases by 1 Ch. 9 |
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Radioactive decay: electron capture |
Sometimes a __________ is captured by the nucleus and the ____________combines with a proton and forms a neutron. The mass number is unchanged and atomic number decreases by 1. Ch. 9 |
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Parent |
An unstable radioactive isotope |
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Daughter products |
Isotopes resulting from the decay of the parent isotope Ch. 9 |
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Radiometric Dating |
The procedure of calculating the absolute ages of rocks and minerals that contain certain radioactive isotopes Ch. 9 |
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Half-life |
The time required for one-half of the atoms of a radioactive substance to decay Ch. 9 |
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Radiocarbon (carbon-14) dating |
The radioactive isotope of carbon is produced continuously in the atmosphere and used in dating events from the very recent geologic past Ch. 9 |
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Eons |
The largest time unit on the geologic time scale, next in order of magnitude above era Ch. 9 |
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Phanerozoic eon |
Part of geo time represented by rocks containing abundant fossil evidence (540 million years-present) Ch. 9 |
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Eras |
A major division on the geologic time scale; they are divided into shorter units called periods Ch.9 |
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Paleozoic Era |
A time span between the Precambrian and Mesozoic eras (542 million-251 million years ago. Ch. 9 |
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Mesozoic Era |
A time span between the Paleozoic and Cenozoic eras (248-65.5 million years ago) Ch. 9 |
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Cenozoic Era |
A time span beginning about 65.5 million years ago, following the Mesozoic era. Ch. 9 |
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Period |
A basic unit of the geo time scale that is a subdivision of era; they may be divided into smaller units called epochs Ch. 9 |
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Epoch |
A unit of geologic time that is a subdivision of a period |
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Archean Eon |
The first eon of Precambrian time. The eon preceding the Proterozoic (between 4.5-2.5 billion years ago) Ch. 9 |
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Proterozoic Eon |
The eon following the Archean and preceding the Phanerozoic (between 2500 and 542 million years ago) Ch. 9 |
