1. Nuclear Radiation ??? Radioactivity (Nuclear Decay)
Henri′ Becquerel
Marie Curie
???
1896 Becquerel accidentally develops photo plate with U salts w/o sunlight
Curies exp. and named it radioactivity. Both won Nobel Prize in Physics, she won for Chem later. Died 1934 leukemia.
Radioactivity (Nuclear Decay)
spontaneous emission of high-energy radiation (charged particles, uncharged particles, or light) from the nucleus of an atom

2. The becquerel (symbol: Bq) is the SI derived unit of radioactivity. 
1896 Becquerel accidentally develops photo plate with U salts w/o sunlight.
Curies conducted experiments and named the “invisible rays” radioactivity. Both won Nobel Prize in Physics, she won for Chem later. Marie Curie died in 1934 of Aplastic anemia.

3. Source of Nuclear Radiation
Strong Nuclear Force
binds protons and neutrons together in the nucleus.
stronger than electric repulsive force over very short distances. + +

4. 3 Types of Nuclear Radiation
Stopped by
animation
Symbol
Charge
Mass
Alpha Particle ()
helium nucleus +2 4
paper
Beta Particle (–)
electron
(smaller, faster)
aluminum –1
Gamma Ray ()
high-energy light (fastest)
3 feet of
Concrete
or Lead

5. 3 Types of Nuclear Radiation
Penetrating: Least to Most  – 
Video clip is “Radioactivity” from Safari playlist (4 min)
or Concrete

6. 3 Types of Nuclear Radiation
2 p + 2 n
Alpha (a) +
Beta (b–) e–
Gamma (g)

7. Certain elements are radioactive because their atoms have
Quick Quiz!
Certain elements are radioactive because their atoms have
more neutrons than electrons.
an unstable nucleus.
a small nucleus.
more neutrons than protons. 7

8. Which property does NOT describe an alpha particle?
Quick Quiz.
Which property does NOT describe an alpha particle?
+2 charge
a relatively large mass
a negative charge
low penetrating power 8

9. Quick Quiz.
When a radioactive nucleus releases a high-speed electron, the process can be described as
oxidation.
alpha emission.
beta emission.
gamma radiation. 9

10.  Quick Quiz. Which of the following is the symbol of a beta particle?10