We have here Radon Rn with mass number = 86 protons + 136 neutrons = 222. Therefore, we have Rn222. The alpha radiation emits particles in the same size of the He atom whose mass number equals 4. By subtracting 4 from 222 we get 218 which is the mass number of Polonium Po218 with 84 protons and 134 neutrons.
Therefore, the right answer is C.
The atom absorb the light in the discrete packet in the photons
The solution for this problem would be:
H + ions from pH = 4.0 x 10^-4 moles.
But H2SO4 gives off 2 moles of H+ ions / mole.
Moles of H2SO4 = 2.0 x 10^-4
Mass = 2 x 10^-4 moles x 98 = 1.96 x 10^-3 grams
1.96 x 10^-3 grams / 10^3 = 1.96 x 10^-6 Kg.