The isotope you are inquiring about is called Argon-40.
To understand why, let’s break down the components:
- The number of protons in an element defines what that element is. With 18 protons, we identify the element as Argon (Ar).
- Neutrons, on the other hand, contribute to the mass of the atom and can vary between different isotopes of the same element.
To find the mass number of an isotope, you simply add the number of protons and neutrons together. For Argon-40:
- Protons: 18
- Neutrons: 22
Mass number = 18 + 22 = 40. Thus, the complete name of this isotope is Argon-40.
In summary, Argon with 18 protons and 22 neutrons is specifically termed Argon-40, based on its atomic structure.