Question

Be sure to answer all parts. In 2006, an ex-KGB agent was murdered in London. Subsequent investigation showed that the cause of death was poisoning with the radioactive isotope 210Po, which was added to his drinks/food. (a) 210Po is prepared by bombarding 209Bi with neutrons. Write an equation for the reaction. Show the mass number and atomic number of all species. Tip: use the sup-subscript button to insert all symbols. (b) Who discovered the element polonium? Marie and Pierre Curie Enrico Fermi (c) The half-life of 210Po is 138 d. It decays with the emission of an α−particle. Write an equation for the decay process. Show the mass number and atomic number of all species. Tip: use the sup-subscript button to insert all symbols. (d) Calculate the energy of an emitted α−particle. Assume both the parent and daughter nuclei to have zero kinetic energy. The atomic masses are: 210Po (209.98285 amu), 206Pb (205.97444 amu), α−particle (4.00150 amu). (Enter your answer in scientific notation). × 10 J (e) Ingestion of 1.0 mg of 210Po could prove fatal. What is the total energy released by this quantity of 210Po, assuming every atom decays? (Enter your answer in scientific notation). × 10 J

Answer 1

(a) atomic number for Bi is 83 and mass number is given as 209. When neutrons are bombarded then it capture neutron (₀n¹) and its mass number increases by 1 unit. Then beta (_-1e⁰) takes place and atomic number increases by 1 unit and we get ₈₄Po²¹⁰. Reaction would be shown as....

₈₃Bi²⁰⁹ + ₀n¹ ------> ₈₃Bi^{210 --------->}₈₄Po²¹⁰ + _-1e⁰

(b) Marie Curie and Pierre Curie discovered Polonium when they were refining Uranium from Pitchbland. Unrefined Pitchbland was noticed to be more radioatice than Uranium taht they got from Pitchbland. After a hard work they refiened Polonium from Pitchbland.

(c) Alpha particle is helium nucleus, ₂He⁴. On alpha decay, mass number decreases by 4 units and atomic number decreases by 2 units. The equation could be shown as....

₈₄PO²¹⁰ --------> 2He⁴ + ₈₂Pb²⁰⁶

(d) From law of mass conservation, mass of reactants must be mass of products.But for nuclear reactions the difference is found, mass of products is less than mass of reactants and this difference in mass is known as "mass defect."

4PO²¹⁰ --------> 2He⁴ + ₈₂Pb²⁰⁶

mass defect = 209.98285 - 4.00150 - 205.97444

mass defect = 0.00691 amu

This mass is converted into energy.

1 amu = 1.66 x 10^-27kg

so, 0.00691 amu x 1.66 x 10^-27kg/amu = 1.147 x 10^-29 kg

from Einstein energy equation, E = mc²

where E is energy, m is mass defect in kg and c is peed of light, 3.0 x 10⁸ m/s

E = 1.147 x 10^-29 kg x (3.0 x 10⁸ m/s)² = 1.0323 x 10^-12 kg m²s^-2

we know that, ( J = kg m²s^-2)

so, E = 1.0323 x 10^-12 J (Answer)

(e) atoms of Po = 1.0 mg x 0.001g/1mg x 1mol/209.98285g x 6.022 x 10²³atom = 2.87 x 10^-18 atoms

in part (d) the energy that we have calculated is energy released for the decay of 1 atom of Po. So, the energy for the decay of 2.87 x 10^-18 atoms would be = 1.0323 x 10^-12 J/atom x 2.87 x 10^-18 atoms = 2.96 x 10^-30 J (answer)