the element radium has a mass number of 226 and an atomic number of 88. how many neutrons does an atom of radium have?

Question

88
314
138
226

Answer 1

To find the number of neutrons in an atom of radium, subtract the atomic number (number of protons) from the mass number.

Number of neutrons = mass number - atomic number
Number of neutrons = 226 - 88
Number of neutrons = 138

Therefore, an atom of radium has 138 neutrons.