Question

Zinc-64 undergoes beta decay as shown:

Answer 1

Symbol for X : $\tt _{31}^{64}Ga$

Further explanation

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

• alpha α particles ₂He⁴
• beta β ₋₁e⁰ particles
• gamma particles ₀γ⁰
• positron particles ₁e⁰
• neutron ₀n¹

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

$\tt _{30}^{64}Zn\Rightarrow _{31}^{64}Ga+~_{-1}^0\beta$