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 or charged particles from the nucleus of an atom

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

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

4. 3 Types of Nuclear Radiation
Stopped by
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. Nuclear Decay Rates
Half-Life

8. 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. 8

9. 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 9

10. Quick Quiz.
When a radioactive nucleus releases a high-speed electron, the process can be described as
oxidation.
alpha emission.
beta emission.
gamma radiation. 10

11.  Quick Quiz. Which of the following is the symbol of a beta particle?11