Final answer:
Isotope symbols consist of the element's symbol followed by the mass number, indicating specific isotopes such as 16N for nitrogen-16 and 25Na for sodium-25.
Step-by-step explanation:
The student is asking for isotope symbols for several elements, including nitrogen, sodium, boron, silicon, calcium, and sulfur, accompanied by specific atomic mass numbers.
Nitrogen-16 would be represented as 16N since nitrogen's atomic number (number of protons) is 7. Similarly, the other isotope symbols would be 25Na for sodium-25, 12B for boron-12, 32Si for silicon-32, 39Ca for calcium-39, and 38S for sulfur-38. These symbols reflect each element's atomic number and the specific isotope's mass number (the sum of protons and neutrons).