Nuclear Equations
Key Questions

First some definitions:
A. Isotopes  atoms with the same number of protons, but a different number of neutrons (same element, different isotopic mass).
Carbon can exist the isotopes carbon12, carbon13, and carbon14. They both have 6 protons (or else they wouldn't be carbon), but a different number of neutrons.
C12 has 6 protons and 6 neutrons
C13 has 6 protons and 7 neutrons
C14 has 6 protons and 8 neutronsB. Radioactive nucleus  a nucleus that spontaneously changes and emits (releases) energy. This occurs spontaneously: by itself and with no outside energy required. Many isotopes do it naturally.
All nuclei with more than 84 protons (Polonium and up) are radioactive. As well as those with with more neutrons than protons Carbon14 is radioactiveBalancing: The sum of the isotopic masses (top numbers) are equal on both sides of the equation.
The sum of the atomic numbers (the bottom numbers) also are equal on both sides of the equation.

Nuclear equations represent the reactants and products in radioactive decay, nuclear fission, or nuclear fusion.
Instead of chemical equations where it shows the different number of elements is conserved in a reaction, in a nuclear reaction the atomic mass and proton number are conserved.
In these examples the sum of the masses (top) and the sum of the proton numbers (bottom) are the same on both sides:
#""_3^6Li+""_1^2H>2""_2^4alpha# As you can see the elements haven't been conserved, but the mass number and proton number have
#6+2=2*4# , and#3+1=2*2# Another example:
#""_6^(14)C>""_7^(14)N+""_(1)^0beta# Again, in this equation, the elements haven't been conserved, by the mass number and proton number have
#14=14+0# , and#6=71#