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)

Explanation:

Step1: Recall neutron - proton relationship

The number of neutrons $n$ in an atom is given by the formula $n = A - Z$, where $A$ is the mass number and $Z$ is the atomic number.

Step2: Identify values for radium

For radium, $A = 226$ (mass number) and $Z=88$ (atomic number).

Step3: Calculate number of neutrons

$n=226 - 88=138$.

Answer:

138