Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?(1 point)
Responses
13
13
5
5
4
4
9
4
To determine the number of neutrons in an isotope of an element, subtract the atomic number from the mass number. The mass number is the sum of the number of protons and neutrons in the nucleus of an atom.
In this case, the isotope is beryllium-9. The atomic number of beryllium is 4. Subtracting the atomic number (4) from the mass number (9) gives us:
9 - 4 = 5
Therefore, the isotope beryllium-9 has 5 neutrons.