Isotopes are different versions of a chemical element. They all have the same number of protons but a different number of neutrons. This change in neutrons makes their atomic mass different, but they still belong to the same element.

Key Points about Isotopes:

1. Protons and Neutrons:

   • An element is identified by its number of protons. This is called the atomic number (Z).
   • Isotopes share the same atomic number (Z) but have different mass numbers (A).

2. Mass Number Calculation:

   • The mass number (A) is the total number of protons and neutrons in an atom.
   • You can calculate it using this simple formula:
     • A = Z + N
     • Here, N stands for the number of neutrons.

3. Examples:

   • Carbon has three main isotopes:
     • Carbon-12 (12C): 6 protons and 6 neutrons
     • Carbon-13 (13C): 6 protons and 7 neutrons
     • Carbon-14 (14C): 6 protons and 8 neutrons
   • In these, the number of neutrons changes from 6 to 8, but the number of protons stays the same at 6.

4. Abundance:

   • Isotopes can be found in nature in different amounts. For example:
     • Carbon-12 (12C) makes up about 98.89% of all carbon.
     • Carbon-13 (13C) is about 1.11%.
     • Carbon-14 (14C), which is radioactive, is found in very tiny amounts (less than 0.0000001%).

Understanding isotopes is really important. It helps in fields like nuclear chemistry, figuring out how old things are (like ancient artifacts), and even in medicine.