Question

the element radium has a mass number of 226 and an atomic number of 88. how many neutrons does an atom of radium have? (1 point) 314 226 138 88

Explanation:

Step1: Recall the formula

The mass number ($A$) is the sum of protons ($p$) and neutrons ($n$), i.e., $A=p + n$. The atomic number ($Z$) is equal to the number of protons. So, $n=A - Z$.

Step2: Substitute values

Given $A = 226$ and $Z=88$. Then $n=226 - 88$.

Step3: Calculate the result

$226-88 = 138$.

Answer:

C. 138