Nothing needs to really be conserved in a nuclear equation: let me just illustrate one alpha and one beta equation to emphasise this.
alpha
Pu-238 (Plutonium, 238) decays by alpha emission to form an atom, which atom is this?
In an alpha 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 + alpha
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.
beta
When writing a beta 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 (beta) particle. Because a new proton has formed, the atomic number of the original atom will increase by 1.
I-131 -> Xe-131 +beta
Nothing is being conserved in this equation.