Note that you can work out the number of neutrons by subtracting the atomic number from the mass number. In this example, it is 35 – 17 = 18 neutrons.

and the sum of the protons and neutrons gives the atomic mass, the number of neutrons defines the isotope of that element. For example, most carbon (≈ 99 %) has 6 protons and 6 neutrons and is written ...

7}^{14}\textrm{N}\) and \(_{6}^{14}\textrm{C}\) are not isotopes. They have the same mass number, A, but different atomic number, Z, and different chemical symbol - they are not the same element.

Many atomic nuclei have a magnetic field similar to that of Earth. However, directly at the surface of a heavy nucleus such ...