The element radium has a mass number of 226 and an atomic number of 88. How many neutrons does an atom of radium have?
A. 226
B. 314
C. 88
D. 138
To find the number of neutrons, we need to subtract the atomic number 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.
Answer: D. 138
To find the number of neutrons in an atom, you subtract the atomic number from the mass number.
For radium, the mass number is 226 and the atomic number is 88.
Neutrons = Mass number - Atomic number
Neutrons = 226 - 88
Neutrons = 138
Therefore, an atom of radium has 138 neutrons.
The correct answer is D. 138.
To find the number of neutrons in an atom, you can subtract the atomic number from the mass number.
In this case, the mass number of radium is 226 and the atomic number is 88.
Neutrons = Mass number - Atomic number
Neutrons = 226 - 88
Neutrons = 138
Therefore, an atom of radium has 138 neutrons.
The answer is D. 138.