Focus On Life Science: California Grade 7

Lesson 2: Absolute Ages of Rocks

Standards Check

1.
__________ are atoms of the same element that have different numbers of neutrons. 4.d
A)Isotopes
B)Compounds
C)Alpha particles
D)Beta particles
2.
Which of the following would cause a nucleus to be unstable? 4.d
A)equal numbers of protons and neutrons
B)too many neutrons
C)protons and neutrons packed tightly in the nucleus
D)the release of an alpha particle from americium-241 in a smoke detector
3.
__________ is the release of nuclear particles and energy. 4.d
A)Atomic half-life
B)Transmutation
C)Radioactive decay
D)Carbon dating
4.
The __________ of a radioactive isotope is the amount of time it takes for half of a sample of the element to decay. 4.d
A)transmutation rate
B)atomic number
C)rate of degradation
D)half-life
5.
Carbon-14 is useful in determining __________. 4.d
A)the best method for the disposal of a radioactive sample
B)how fast a radioactive sample will decay
C)the age of dead plants and animals
D)the age of sedimentary rock layers
6.
What do scientists use to help them determine the absolute age of rocks and other objects? 4.d
A)the number of atoms they are made of
B)the properties of the atoms they are made of
C)the properties of the fossils they are made of
D)their weight
7.
What type of method do scientists use to determine correlation of rock layers? 4.d
A)fossil evidence
B)radioactive decay
C)half-life
D)all of the above
8.
Rocks that can be dated radiometrically are mostly __________. 4.d
A)igneous and metamorphic rocks
B)igneous and sedimentary rocks
C)sedimentary and metamorphic rocks
D)metamorphic rocks
9.
Radiometric dating has been used to date the oldest rocks on Earth, and scientists now estimate Earth to be __________. 4.d
A)3.96 billion years old
B)4.6 billion years old
C)a few thousand years old
D)2.0 billion years old
Grade 7
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