1. Nuclear Chemistry
Bravo – 15,000 kilotons

2. Nuclear Chemistry Chemical Reactions: Nuclear Reactions:
Changes in Valence e-
Woosh bottle, Flame test, Gummy Bear Sacrifice, etc.
Nuclear Reactions:
Changes in nucleus
Chain reactions, atomic bomb, etc.
Radioactivity:
Spontaneous emission of radiation from an atom.
3 kinds of radiation given off:
1. Alpha radiation
2. Beta radiation
3. Gamma radiation

3. Stable Nuclei Stable Nucleus is not radioactive
Stability depends on P+ and Neutron combination
Nucleus = +’s & 0’s in a small space (likes repel)
STRONG NUCLEAR FORCE keeps the nucleus stable
Neutrons add to the Strong Nuclear Force
(Act as the glue that holds the nucleus together)
Elements 1-20 the protons generally = neutrons
Elements the neutrons increasingly outnumber the protons
Elements 83 on up, there becomes too many extra neutrons to keep the nucleus stable and it becomes radioactive.
Generally isotopes that are too heavy (2 many neutrons) or too light (2 few neutrons) are radioactive.

4. Alpha Radiation
Alpha Particle = 2 protons & 2 neutrons (helium nucleus)
Only travel a few cm through air
Paper or clothing can stop them
Safe, unless the source is inside of your body 4 2 4 2  He

5. Beta Radiation
Beta particles=high speed e- from nucleus (not from cloud)
A neutron changes into 1 proton and 1 electron
The electron speeds out and the proton stays in the nucleus
About 100 times more penetrating than alpha particles.
Penetrates 1-2 mm into solid objects and could damage the skin
Must wear heavy clothing to stop them -1 e -1 

6. Gamma Radiation
Gamma radiation = are very energetic, but are not particles
Are very similar to X-Rays
They often accompany alpha and beta radiation
Are stopped by concrete or lead 

7. Nuclear Reactions
When an atom emits any of these forms of radiation, radioactive decay occurs. Below is an example of a nuclear reaction:
Beta decay of iodine-131:
In radioactive decay, the sum of the atomic #’s & the mass #’s is the same before and after the reaction.
131 53
131 54 I Xe -1 e

8. Nuclear Symbols Element Mass number symbol (p+ + no) Atomic number
(number of p+)

9. Types of Radioactive Decay
alpha production (a, He): helium nucleus
beta production (b, e):
gamma ray production (g):

10. Uranium-238 Radioactive Decay Series
Radioactive Decay Series of 238U
238U92 ® 234Th a2
234Th90 ® 234Pa b– +
234Pa91 ® 234U92 + b– +
234U92 ® (continue)
206Pb82

11. Penetration Alpha (Low)- blocked by paper or skin
Beta (medium) – medium wood, thin sheet of metal (foil)
Gamma (high)-Thick concrete or lead

12. Alpha Particle Emission Beta Particle Emission%
Alpha Particle Emission
Beta Particle Emission
Gamma Ray Emission
Symbol or
Mass
Heavy
Light
No Mass
How it changes the nucleus
Decreases the mass number by 4
Decreases the atomic number by 2
Converts a neutron into a proton
Increases atomic number by 1
No change to the nucleus
Penetration
Low
Medium
High
Protection provided by…
Skin
Paper, clothing
Lead
Danger