The element used for dating the ancient remains is

The radionuclide $_{90}^{234}Th$ undergoes two successive $\beta$-decays followed by one $\alpha$-decay. The atomic number and the mass number respectively of the resulting radionuclide are

When a radioactive nucleus emits an $\alpha$-particle,the mass of the atom

Describe the rays emitted by radioactive elements.

In the radioactive decay $_{92}X^{232} \to _{89}Y^{220}$,how many $\alpha$ and $\beta$-particles are ejected from $X$ to form $Y$?

During a negative $\beta$-decay: