Answer:
To find the number of neutrons in an atom, you can subtract the number of protons from the mass number. The mass number (A) is the sum of protons and neutrons in an atom.
For Na-23:
- Number of protons (atomic number, Z) = 11
- Mass number (A) = 23
Number of neutrons (N) = Mass number (A) - Number of protons (Z)
N = 23 - 11 = 12
So, Na-23 has 12 neutrons.
Therefore, the correct answer is:
b. 12
Explanation:
