Uranium-238 undergoes radioactive decay according to the incomplete below. 238 92
U= 4
2 He + X.
What is the decay product represented by X?

The decay product represented by X : Thorium (Th) : ²³⁴₉₀Th

Further explanation

Given

Decay reaction

²³⁸₉₂U ⇒ ⁴₂He + X

Required

The decay product

Solution

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

In a decay reaction, the sum of the mass number and atomic number of the elements in the reactants and products must be the same

So the mass number of the element X = 238 - 4 = 234

Atomic number of the element X = 92 - 2 = 90

If we look at the periodic system, then the element with atomic number 90 is Thorium (Th)

Protons = 14 Neutrons = 16 This is an isotope of silicon. The 30 is the sum of the number of protons and neutrons in silicon. The 14 is simply the atomic number of silicon which is 14. So the number of neutrons is 30 - 14 = 16. So the answer is: Protons = 14 Neutrons = 16