Isotopes include two or more versions of an atom of a given element that have the same number of protons but a different number of neutrons. An isotope symbol communicates information about the element (specifically, the symbol), the atomic number of that element, and the mass number of the specific isotope of the atom.
 

Activity 2 - Isotope Symbols I - is all about constructing the isotope symbol from information about the atom. Refer to the Fundamentals section (above) to acquire the basic information. Then study the graphic below.