Question

which values do scientists compare when using potassium - argon dating? the number of stable and unstable parent atoms the number of non - decayed elements left in the rock the amount of parent and daughter material trapped in the rock the amount of gas from the decayed material that has escaped from rock

Explanation:

Potassium - argon dating is a radiometric dating method. In radiometric dating, the principle is based on the decay of parent isotopes (in this case, potassium - 40) into daughter isotopes (argon - 40). Scientists compare the amount of parent material (potassium - 40) and daughter material (argon - 40) trapped in the rock. The ratio of these two amounts, along with the known decay rate of potassium - 40, is used to calculate the age of the rock.

• The first option about stable and unstable parent atoms is incorrect as potassium - argon dating focuses on the parent - daughter relationship, not just parent atoms.
• The second option about non - decayed elements is too vague. Radiometric dating specifically uses the parent - daughter ratio.
• The fourth option about escaped gas is incorrect because in potassium - argon dating (assuming the rock has been a closed system, which is an assumption in this dating method), we consider the trapped daughter (argon) and parent (potassium) materials, not the escaped gas.

Answer:

the amount of parent and daughter material trapped in the rock