Question

Complete the equation below, and specify whether it is a fission or fusion reaction.Mass Number:Atomic Number:Chemical Symbol:

Answer 1

First, we need to know the total number of mass on the left side. The mass number of H plus He is 5, so the mass number of X must be 1.

Second, the sum of the atomic numbers on the left is 3, so the atomic number of X is 1.

Therefore, the missing element must have a mass number of 1, and an atomic number of 1, its chemical symbol H. It's a fusion reaction because the atom of He is heavier.