When an alpha particle is emitted from a radioactive substance its atomic number(\\\\(Z\\\\)) decreases by \\\\(2\\\\) and mass number(\\\\(A\\\\)) decreases by \\\\(4\\\\). When \\\\(\\beta\\\\) particle is emitted from a radioactive substance its atomic number(Z) increases by \\\\(1\\\\) and mass number(\\\\(A\\\\)) does not change.Here, Uranium decays to lead its mass no changes to by \\\\(24\\\\) i.e. \\\\(\\dfrac{24}{4} = 6 \\alpha\\\\) particles are emitted and hence, its atomic number changes by 12 but the atomic numbre of \\\\(P_b\\\\) is 10 this is due to emission of two \\\\(\\beta\\\\) particle. \\\\(_{92}^{238}\ extrm{U}\\rightarrow 6\\alpha_{2}^{4} + 2\\beta_{1}^{0} + _{82}^{214}\ extrm{Pb}\\\\)