1. 7.1 Atomic Theory and Radioactive Decay

2. Early Pioneers in Radioactivity
Rutherford:
Discoverer Alpha and Beta rays 1897
Roentgen:
Discoverer of X-rays 1895
The Curies :
(Marie, Pierre)
Led to the developing the field of nuclear chemistry
Becquerel:
Discoverer of Radioactivity 1896

3. Periodic Table Form vs. Radioactyive Form
"X" represents the scientific abbreviation given for the symbol
"A” represents the mass number
"Z“ represents the atomic number
Also be written as Carbon-12
12 represents atomic mass 6 C
Carbon
12.0
Periodic Table Form

4. Isotopes and Mass Number
Isotopes have the same number of protons,
But differ in the number of neutrons
An element may have only certain isotopes that are radioactive. These are called radioisotopes

5. Rutherford identified 3 types of radiation
1) Positive alpha radiation α 2) Negative beta radiation β 3) Neutral gamma radiation γ

6. Alpha Radiation 
alpha particles
Positively charged, 2+

7. Beta Radiation (Beta Decay)
Beta partcile
Negatively charged, 1-
neutron  a proton + an electron.

8. Uranium is releasing an Alpha particle, and Gamma Radiation
Gamma decay results from energy being released from a high-energy nucleus., it is shown by:
Gamma radiation has no charge and no mass.
Uranium is releasing an Alpha particle, and Gamma Radiation