Who discovered radioactivity?

If a heavy nucleus has an $N/Z$ ratio higher than that required for stability,then:

Which of the following is deflected by an electric field?

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

Consider the following radioactive decay process:
${ }_{84}^{218} A \stackrel{\alpha}{\longrightarrow} A_1 \stackrel{\beta^{-}}{\longrightarrow} A_2 \stackrel{\gamma}{\longrightarrow} A_3 \stackrel{\alpha}{\longrightarrow} A_4 \stackrel{\beta^{+}}{\longrightarrow} A_5 \stackrel{\gamma}{\longrightarrow} A_6$
The mass number and the atomic number of $A_6$ are given by:

Write nuclear reaction equations for:
$(i)$ $\alpha$-decay of $^{226}_{88}Ra$
$(ii)$ $\alpha$-decay of $^{242}_{94}Pu$
$(iii)$ $\beta^-$-decay of $^{32}_{15}P$
$(iv)$ $\beta^-$-decay of $^{210}_{83}Bi$
$(v)$ $\beta^+$-decay of $^{11}_{6}C$
$(vi)$ $\beta^+$-decay of $^{97}_{43}Tc$
$(vii)$ Electron capture of $^{120}_{54}Xe$