To calculate the number of neutrons in an atom, you need to know its atomic number and its atomic mass. The atomic number tells you how many protons are present in the atom, while the atomic mass (rounded to the nearest whole number) indicates the total number of protons and neutrons in the nucleus.
The formula to find the number of neutrons is:
Number of Neutrons = Atomic Mass – Atomic Number
For example, consider the element Carbon, which has an atomic number of 6 and an atomic mass of about 12. By applying the formula, we get:
Number of Neutrons = 12 (Atomic Mass) – 6 (Atomic Number) = 6 Neutrons
This method works for most stable isotopes of elements. However, keep in mind that some elements can have different isotopes with varying numbers of neutrons, which means the atomic mass can vary slightly. In such cases, the most common isotope’s atomic mass is typically used for these calculations.