To determine the number of neutrons in an atom, you use the following information:
1. Atomic Number (Z): This is the number of protons in the atom. For aluminum (Al), the atomic number is 13.
2. Mass Number (A): This is the total number of protons and neutrons in the atom. For aluminum, the mass number is 27.
The number of neutrons (N) in the atom can be found using the formula:
[tex]\[ \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \][/tex]
Given:
- Atomic number (Z) = 13
- Mass number (A) = 27
Using the formula:
[tex]\[ \text{Number of neutrons} = 27 - 13 = 14 \][/tex]
Therefore, the aluminum atom has 14 neutrons.
The correct answer is:
B. 14
