Which of the following is a radioactive element?

The element used for dating the ancient remains is

Which of the following radioisotopes is used as anticancerous?

If $_{92}U^{236}$ nucleus emits one $\alpha$-particle,the remaining nucleus will have

$A$ radioactive atom $^X_Y M$ emits two $\alpha$ particles and one $\beta$ particle successively. The number of neutrons in the nucleus of the product will be

An element with atomic number $84$ and mass number $218$ loses one $\alpha$-particle and two $\beta$-particles in three successive stages. The resulting element will have: