The most abundant isotope of arsenic is arsenic-75.
Tritium is the most abundant hydrogen isotope
An isotope of cobalt is used to to kill cancer cells. The isotope americium-241 is used in smoke detectors.
Fermium is an extremely rare artificial isotope.
There is only one abundant isotope of fluorine and that is 19FFluorine-19 is the most common isotope, its abundance is classed as 100% because no other Fluorine isotopes exist in significant quantities. It is also the only stable Fluorine isotope.
Potassium I reckon
Boron-11 is the most abundant isotope of boron in nature because it is a stable isotope with a relatively long half-life, making it less likely to decay into other isotopes. Boron-10, another naturally occurring isotope, is less abundant because it is less stable and undergoes neutron capture to form boron-11.
Carbon-12 is the most abundant isotope of carbon, making up about 98.9% of carbon found in nature. Carbon-13 is the second most abundant isotope, making up about 1.1% of natural carbon.
Francium has no stable isotopes. That means it doesn't really have a "most abundant" isotope; they're all pretty much nonexistent. There are trace amounts of 223Fr in uranium minerals, because it's a decay product of 227Ac (which is itself a decay product in the decay chain of uranium).
Without additional information about the specific element in question, it's not possible to determine which isotope is more abundant solely based on the atomic masses. The abundance of isotopes depends on various factors such as stability and nuclear properties of the specific element.
To determine the most abundant isotope in a sample, scientists use a technique called mass spectrometry. This method measures the mass-to-charge ratio of isotopes in the sample, allowing researchers to identify the isotope that appears in the highest abundance.
The isotope with a mass of 32 amu is the most abundant. This can be determined by comparing the atomic mass of sulfur (32.06 amu) to the masses of the isotopes. Since the atomic mass is closest to 32 amu, this isotope is the most abundant.