If $_{92}U^{238} \to _{Z}X^{A} + _{2}He^{4}$,then $Z$ and $A$ will be ..........

$A$ free neutron decays spontaneously into:

${ }_{90}^{232} \text{Th}$ emits $6 \alpha$ and $4 \beta$ particles and gets converted into lead. The mass number and atomic number of lead is $......$

In a radioactive decay chain,${ }_{90}^{232} Th$ nucleus decays to ${ }_{82}^{212} Pb$ nucleus. Let $N_{\alpha}$ and $N_{\beta}$ be the number of $\alpha$ and $\beta^{-}$ particles,respectively,emitted in this decay process. Which of the following statements is (are) true?
$(A)$ $N_{\alpha}=5$
$(B)$ $N_{\alpha}=6$
$(C)$ $N_{\beta}=2$
$(D)$ $N_{\beta}=4$

In the following equation representing $\beta^{-}$ decay,the number of neutrons in the nucleus $X$ is ${ }_{83}^{210} Bi \longrightarrow X + { }_{-1}^{0} e + \bar{\nu}$

$A$ radioactive decay can form an isotope of the original nucleus with the emission of which particles?