Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?(1 point)

Question

Responses

4
4

5
5

13
13

9

Answer 1

The isotope beryllium-9 has a mass number of 9. The atomic number of beryllium is 4, which means it has 4 protons. To find the number of neutrons in an isotope, you can use the formula:

\[ \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \]

For beryllium-9:

\[ \text{Number of neutrons} = 9 - 4 = 5 \]

So, the isotope beryllium-9 has 5 neutrons.