Answer: the missing parts are ³₂He
Step-by-step explanation:
The equation shown represents a nuclear reaction, meaning that, instead of the two hydrogen atoms form a molecule by a chemcial bond between the electrons of the atoms, the nuclei of the two interacting atoms change, leading to a new kind of atoms and particles.
That is mainly indicated by the appearace of the particle ¹₀ n, which is the symbol for a neutron. The superscript 1 to the left of the symbol (letter n) means that the mass number of the neutron is 1, and the subscript 0 to the left of the symbol means that the atomic number of neutron is 0.
To determine the symbol, superscript and subscript needed to complete the missing parts of the equation, you need to do a mass number and atomic number balance.
Mass number balance:
The mass number is the superscript to the left of the symbol of the atom.
Each hydrgogen atom, in the reactant side, contributes a mass number 2, and the neutron on the product side contributes a mass number 1, so the balance is:
2 + 2 = x + 1,
from which you determine that the unknown mass number is x = 4 - 1 = 3.
Atomic number balance
The atomic number is the subscript to the left of the element.
Each hdyrogen atom contributes an atomic number 1, and the neutron contributes 0 atomic number. So, the atomic number balance is:
1 + 1 = x + 0 ⇒ x = 2.
Hence, the unknown atomic number is 2.
Conclusions:
The atomic number of the unknown element is 2, meaning that it has 2 protons.
In a periodic table you find that the element with atomic number 2 is helium, whose symbol is He.
The mass number of this atom of helium is 3, which implies that it has 3 - 2 = 1 neutron.
Using the corresponding notation, the complete equation is:
²₁ H + ²₁ H → ³₂He + ¹₀ p
hope this helps