The Symbol for a Certain Isotope of Strontium Is ${}^{90}_{38}$ SrWhat Is the Mass Number of This Isotope?
A)38
B)52

question 44

Multiple Choice

The symbol for a certain isotope of strontium is ${}^{90}_{38}$ Sr.What is the mass number of this isotope?

• A)38
• B)52
• C)88
• D)90
• E)128

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