Zinc-64 undergoes beta decay as shown: GA Zn AX+ Lie
Enter the appropriate values for A and Z and the chemical
symbol for X.

Symbol for X :

Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,  

Zinc-64 undergoes beta decay, so :

The atomic number will increase by +1, and the mass number will remain the same

So that the atomic number:

30 + 1 = 31

The element with atomic number 31 is Gallium

Reaction

c (diamond),

sio2 (quartz)

frequency, z, and the collision density, z, in carbon dioxide (co2), r 180 pm at 30 °c and 120 kpa