Examination of salts

Principle

Potassium belongs to the naturally radioactive substances, alongside uranium and thorium. With its 2.6 percent by weight, it is among the 10 most frequently occurring elements in the earth's crust, and is present in numerous minerals as well as in all organic substances. Potassium found in nature is composed of 3 isotopes, K- 39 to 93.2581%, K-41 to 6.7302% and the radioactive isotope K-40, which is only present to 0.0117%. It decays with a half-life of 1.27·109, to 89.3% probability through beta decay and 10.7% probability through K capture and emission of gamma rays.
The specific activity of K-40 is very low because of the long half-life, so that students can experiment with any amount of it without reservation.

It is widely used in the form of potash as a fertilizer and as baking powder. Because it is so widespread, potassium is responsible for about 12% of the naturally occurring radioactivity which we are exposed to. The human body contains on average about 15 g of potassium, and this generates 3 to 5 kBq of radioactivity.

Task

To determine which of the salts provided are radioactive.

Literature for this article als follows

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