When a radioactive substance emits an $\alpha$- particle, its position in the periodic table is lowered by
One place
Two places
Three places
Four places
A nucleus $_n{X^m}$ emits one $\alpha$ particle and two $\beta$ particles. The resulting nucleus is
In the nuclear reaction $_{85}{X^{297}} \to Y + 4\alpha ,\;Y$ is
What is the respective number of $\alpha $ and $\beta $ particles emitted in the following radioactive decay
$_{90}{X^{200}}{ \to _{80}}{Y^{168}}$
A nucleus of lead $Pb _{82}^{214}$ emits two electrons followed by an $\alpha$-particle. The resulting nucleus will have
In the disintegration series the $_{92}^{238}U\xrightarrow{\alpha }X\xrightarrow{{\beta - }}_Z^AY$ values of $Z$ and $A$ respectively will be