An element ${ }_{x} A^{y}$ emits $5$ $\alpha$ and $4$ $\beta$ particles to give ${ }_{82} B^{207}$. The number of protons and neutrons in $A$ are respectively

In the nuclear reaction $_3Li^6 + (?) \to _2He^4 + _1H^3$,the missing particle is:

What is $X$ in the following reaction?
${}_{12}Mg^{26} + {}_{1}H^{2} \longrightarrow {}_{12}Mg^{27} + X$

An artificial radioactive isotope gave $_7^{14}N$ after two successive $\beta$-particle emissions. The number of neutrons in the parent nucleus must be

The radioactive isotope $_{27}^{60}Co$,which is used in the treatment of cancer,can be produced by an $(n, p)$ reaction. For this reaction,the target nucleus is:

$A$ closed vessel with rigid walls contains $1 \ mol$ of ${ }_{92}^{238} U$ and $1 \ mol$ of air at $298 \ K$. Considering the complete decay of ${ }_{92}^{238} U$ to ${ }_{82}^{206} Pb$, the ratio of the final pressure to the initial pressure of the system at $298 \ K$ is: