January 2020 NY Regents Chemistry Exam
48 Which emission causes the atomic number of a nuclide to decrease by 2 and its mass number to decrease by 4?
(1) an alpha particle
(2) a beta particle (3) gamma radiation
(4) a positron
Solution: The question is asking us which nuclear particle has an atomic number of 2 and mass number of 4. Looking at Table O on the Reference Table, we see that alpha particle has a mass number of 4 and an atomic number of 2.
Answer: 1
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