Page 207 - Science Course 1 (Book 1)
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Mo6-L2: Vocabulary Review
Directions: On each line, write the term from the word bank that correctly replaces the underlined words in
each sentence. NOTE: You may need to change the form of a term
atomic number average atomic mass ion isotope
mass number nuclear decay radioactive spontaneous
1. Carbon-12, carbon-13, and carbon-14 are examples of atoms of the same element that have different
numbers of neutrons.
2. Radioactive elements emit radiation without external force or cause.
3. Nitrogen’s number of protons is seven.
4. A radioactive element goes through a process in which its unstable atomic nucleus changes into another
more stable nucleus by emitting radiation.
5. Beneath each element’s symbol on the periodic table, there is a number that provides the average mass of
the element’s isotopes, weighted according to the abundance of each isotope for the element.
6. Na+ and F–are examples of atoms that are no longer neutral because they have gained or lost electrons.
7. Uranium is an example of an element that is able to spontaneously emit radiation.
8. Carbon-12 is the most abundant isotope of the element; it has a sum of protons and neutrons equal to 12.
Mo6-L2: Key Concept Organizer
Directions: On the line before each statement, write A if the statement describes alpha decay, B if the
statement describes beta decay, G if the statement describes gamma decay, or T if the statement describes
all three types of nuclear decay.
1. It emits rays that do not contain particles.
2. The atomic number increases by one.
3. It emits radiation.
4. There is no change in the number of protons or neutrons in the atom.
5. It emits a particle made of two protons and two neutrons.
6. It is associated with unstable nuclei.
7. It does not change one element into another.
8. There are two fewer protons and two fewer neutrons in the atom.
9. It occurs when a neutron changes into a proton and a high-energy electron.
10. The atomic number decreases by two.
11. There is one fewer neutron and one more proton in the atom.
12. It is associated with radioactive elements.
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