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35 Cards in this Set
- Front
- Back
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Carbon 12, carbon 13, and carbon 14 are examples of atoms of the same element that have different numbers of neutrons |
isotope |
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radioactive elements emit radiation without external force or cause |
spontaneous |
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nitrogen's number of protons is seven |
atomic number |
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a radioactive element goes through a process in which its unstable atomic nucleus changes into another more stable nucleus by emitting radiation |
nuclear decay |
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beneath each elements symbol on the periodic table, there is a number that provides the average mass of the elements isotopes, weighted according to the abundance of each isotope for the element |
average atomic mass |
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Na+ and F- are examples of atoms that are no longer neutral because they have gained or lost electrons |
ion |
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uranium is an example of an element that is able to spontaneously emit radiation |
radiactive |
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Carbon 12 is the most abundant isotope of the element; it has a sum of protons and neutrons equal to 12 |
mass number |
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protons and _______ have about the same __________ |
neutrons, mass |
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_________ have much less mass than the other two particles in an atom |
electrons |
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most of the mass of an atom is in the ________ nucleus |
the number of protons in an atom of an element is the elements __________ atomic number |
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different elements contain different numbers of ________ |
protons |
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in a neutral atom, the number of _____ equals the number of protons because the number of ________ charges must equal the number of positive charges |
electrons. negative |
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_______ are atoms of the same element that have different number of ________ |
isotopes. neutrons |
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the total number of __________ and neutrons in an atom is the __________ of an atom |
protons. mass number |
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the _________ of an element is the average mass of the elements _______ |
average atomic mass. isotopes |
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the average atomic mass is _______ according to the abundance of each isotope |
weighted |
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weighted means that the average atomic mass is based on the ________ of each atom in a sample and the number of atoms of that __________ that are present |
mass. isotopes |
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______ first noticed that some elements spontaneously give off _________ |
Henri Beguard. energy |
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_________ called elements that spontaneously emitt radiation _________ |
Marie Curie. radioactive |
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radiation is made of energy and ________ that come from the _____ of radioactive atoms |
particles. nuclei |
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when atoms release particles of radiation, they change to different ______ |
element |
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_________ is a process that occurs when an unstable _________ changes into another more stable nucleus by emitting |
nuclear decay. nucleus |
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nuclear decay can produce three different types of ________ |
radiation |
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a ______ particle consists of _______ protons and two __________ |
alpha. two. neutrons |
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when alpha decay occurs, the atomic number of each atom that decays _________ by ________ |
decreases. two |
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_________ decay occurs when a neutron in at atom changes into a __________ and a high energy electron called a __________ particle |
beta. proton. beta |
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when beta decay occurs, the atomic number of an atom ______- by ___________ |
increases. one proton |
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gamma rays contain a lot of _______ but no ______ |
energy. particles |
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_______ rays are sometimes emitted during nuclear decay, but this decay does not change one element into another element |
gamma |
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energy released during radioactive decay can be either _________ or harmful |
beneficial |
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an _________ is an atom that is no longer neutral because it has gained or lost ______ |
ion. electrons |
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a positive ion is an atom that has ______ electrons |
lost |
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a negative ion is an atom that has ________ electrons |
gained |
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study |
good luck |
