Nothing needs to really be conserved in a nuclear equation: let me just illustrate one α and one β equation to emphasise this.
α
Pu-238 (Plutonium, 238) decays by α emission to form an atom, which atom is this?
In an α decay equation, we lose an atomic number of 2 an a mass number of 4 - this is the equivalent of a Helium (He) atom. So,
Pu−238→U−234+α
Uranium is formed because it is element number 92 - Plutonium is element number 94, so if we take two away from 94 we get 92 which is the atomic number of U. There is nothing conserved in this reaction.
β
When writing a β equation, remember that in the nucleus, a neutron (n) decays into a proton (p+) and a high energy electron which is known as the beta (β) particle. Because a new proton has formed, the atomic number of the original atom will increase by 1.
I−131→Xe−131+β
Nothing is being conserved in this equation.