Competency #5
Answer and Explanation
The correct answer is 84 protons and 126 neutrons.
Protons: Since we know the element is polonium ( Po) we know there are 84 protons by finding this element on the periodic table (Group 6A, period 6).
Neutrons: The mass number of this isotope was 210 amu (given).
Mass number = # protons + # neutrons
We can rearrange the above equation to:
# neutrons = Mass number - # protons
# neutrons = 210 - 84
# neutrons = 126
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