1. Nuclear Chemistry

2. Nuclear Chemistry

3. Radioactivity
One of the pieces of evidence for the fact that atoms are made of smaller particles came from the work of Marie Curie ( ).
She discovered radioactivity, the spontaneous disintegration of some elements into smaller pieces.

4. Nuclear Reactions vs. Normal Chemical Changes
Nuclear reactions involve the nucleus
The nucleus opens, and protons and neutrons are rearranged
The opening of the nucleus releases a tremendous amount of energy that holds the nucleus together – called binding energy
“Normal” Chemical Reactions involve electrons, not protons and neutrons

5. Mass Defect
It is experimentally observed that the mass of an atom (containing neutrons) is always slightly less than the sum of the masses of its component particles. The difference between the atomic mass and the sum of the masses of its protons, neutrons, and electrons is called the mass defect.

6. Isotope
Should Weigh:
Does Weigh:
Mass Defect:
Deuterium =
2.0140
0.0025
Tritium
(1.0087) =
0.0092
The loss in mass is accounted for by Einstein's E = mc2, which describes conversions between matter (m) and energy (E). When the nucleus is being formed, some matter was converted into energy (called nuclear binding energy).

7. There are four types of nuclear reactions:
Natural radioactive decay: transmutations occur by natural radioactivity
Artificial transmutation: transmutations occur by nuclear disintegration caused by external stimulation as a scientist bombards a nucleus with a particle
Fission: certain nuclei having a large mass are bombarded with special particles that cause the nuclei to split into two nuclei each having a smaller mass;
Fusion: nuclei of light elements are combined to form heavier nuclei.
The ability of a nucleus to emit a nuclear particle and energy without external stimulation
The addition of another nuclear particle makes the nucleus unstable

8. The “Must-Know” Nuclear Particles

9. Penetrating Ability Gamma rays pose the greatest external risk
Alpha pose the greatest risk if emitted from ingested radioactive particles

10. The table below contains information about nuclear reactions involving the emission of radiation.
NUCLEAR CHANGES
Type of Reaction
Radiation
(Particle)
Effect on the
Atomic Number
Atomic Mass
Alpha emission (α)
42He
decrease by 2
decrease by 4
Beta emission (β)
0-1e or β
increase by 1
no change
Positron emission (β+)
01e or β
decrease by 1
Gamma emission
00γ
Electron capture (EC)

11. Nuclear reactions that involve bombardment of nuclei vary in their products. For example:
94Be He → 126C n
147N He → 178O H
2713Al H → Al H
4521Sc n → K He

12. Nuclear Reactions

13. Balancing Nuclear Reactions
In the reactants (starting materials – on the left side of an equation) and products (final products – on the right side of an equation)
Atomic numbers must balance
and
Mass numbers must balance
Use a particle or isotope to fill in the missing protons and neutrons

20. 10B + 4He N + 1n
nitrogen
radioisotope

21. Write the nuclear equation for the
Beta emitter Co-60.
60Co Ni + 0 e

22. LC: Writing Nuclear Equations
Uranium-235 is bombarded with 1 neutron in an artificial transmutation. Krypton-92 and Barium- 141 are released, as well as some neutrons. How many neutrons are released?

24. Practice: Examples

25. Technetium-99 (9943 Tc) decays by beta emission to form ruthenium-99 (9944 Ru).
Phosphorus-32 decays by beta emission to form sulfur-32.
________ He → 126C n
42He + _________ → Pu n n