234 is the mass number of the resulting element that is uranium.
Explanation:
Beta-decay is nuclear process in whicha neutron gets converted into a proton and an electron releasing a beta-particle. The beta particle released carries a charge of -1 units.
So, when protactinium-234 undergoes beta decay to form uranium-234 as resultant element.
The reaction can be expressed as:
234 is the mass number of the resulting element that is uranium.
Answer is: mass number is 234. Beta decay is radioactive decay<span> in which a </span>beta ray<span> and a </span>neutrino<span> are emitted from an </span><span>atomic nucleus. </span>There are two types of beta decay: beta minus<span> and </span>beta plus. <span> In beta minus </span><span>decay, neutron is converted to a proton and an </span>electron<span> and an </span>electron antineutrino and in beta plus <span>decay, a proton is converted to a neutron and </span>positron<span> and an </span>electron neutrino, so mass number does not change.