Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?(1 point)
Responses
13
5
4
9
The isotope beryllium-9 has 5 neutrons.
To find the number of neutrons in an isotope, subtract the atomic number from the mass number.
The isotope beryllium-9 has a mass number of 9. The atomic number of beryllium is 4.
Therefore, the number of neutrons in beryllium-9 is 9 - 4 = 5.
So the answer is 5.