Transcript 01Whatisradon9-7

Lesson 1
What is radon?
Which characteristics
apply to radon?
• Liquid
• Gas
• Solid
• Colorless
• Grayish-green
• Greenish-blue
• Smells like ozone
• Has no smell
• Has no taste
• Tastes metallic
• Tastes like chicken
See handout 1-1
• Occurs in nature
• Made by humans
• Reacts readily chemically
• Does not readily react chemically
(is inert)
• Has a static electrical charge
• Has no static electrical charge
• Radioactive
• Not radioactive
• Harmful to human health
• Harmless to human health
Slide 1-1
Characteristics of radon
• Liquid
• Gas
• Solid
• Colorless
• Grayish-green
• Greenish-blue
• Smells like ozone
• Has no smell
• Has no taste
• Tastes metallic
• Tastes like chicken
• Occurs in nature
• Made by humans
• Reacts readily chemically
• Does not readily react
chemically (is inert)
• Has a static electrical charge
• Has no static electrical
charge
• Radioactive
• Not radioactive
• Harmful to human health
• Harmless to human health
Slide 1-2
Is there radon
in this room?
• Why would we care?
– Radon is harmful to human health
– Leading cause of lung cancer among
nonsmokers
• How would we know?
– Radon may occur anywhere
– Radon has no color, odor, or taste, so
we cannot detect with our senses
– We can tell only by measuring
Slide 1-3
Background for
understanding radioactivity
Simple atom
• Nucleus
– Protons (+ or
positive charge)
– Neutrons (no
charge)
• Electrons (- or
negative charge)
Slide 1-4
Radon (Rn) atom
Radon is an element: a basic unit of matter
Atomic number =
Number of protons
86
Atomic mass or
mass number =
Number of protons +
number of neutrons
Varies
Slide 1-5
Naturally occurring
radon isotopes
Isotopes: different forms of an element with
different atomic masses
Number of
protons
Number of
neutrons
Atomic
mass
Radon-219
86
133
219
Radon-220
86
134
220
Radon-222
86
136
222
Slide 1-6
Isotopes
• May be stable or unstable
• Unstable isotopes
(radioactive) decay
spontaneously (change to
another element) called
– Decay products
– Progeny
– Daughters
• During decay, unstable
isotopes give off radiation
Radiation =
energy
emitted as
invisible
• Particles
• Waves
• Rays
Slide 1-7
Radon decay series
Radon-222
Polonium-218
Lead-214
Bismuth-214
Polonium-214
Lead-210
Slide 1-8
Radon and its
decay products
Radon
Decay products
Gas
Solid
Chemically inactive
Chemically active
No static electrical
charge
Electrically charged
Primary source of cell
damage leading to lung
cancer
Slide 1-9
Types of radiation
released
Alpha ()
Beta ()
Gamma ()
Relatively large
mass
Relatively small
mass
No mass
= 2 protons and
2 neutrons
= 1 electron
= pure energy
(electromagnetic
radiation)
Electrical charge of
+2
Electrical charge of
-1
No electrical
charge
Moves slowly
Moves quickly
Moves at the speed
of light
Least penetrating
Moderately
penetrating
Most penetrating
Most damaging to
human health
Slide 1-10
Radiation released in
radon decay
Radon-222
+
Polonium-218
+
Lead-214
+
Bismuth-214
+
Polonium-214
Lead-210
+
Slide 1-11
Example: 1-day half-life in
imaginary box of atoms
100
100.00
80
Percentage
of atoms
remaining
60
50.00
40
25.00
20
12.50
0
0
1
2
3
4
6.25
5
3.13 1.56 0.78
6
7
Number of days
Slide 1-12
Half-life of radon
3.8 days
In 3.8 days
• Radon can move from soil, rock, and
water into air in a home
– People breathe in the radon
• As radon decays
– It releases radiation
– It creates radon decay products, which may
remain in lungs and release more radiation as
they decay
• Note: Radon gas is continually entering a
home and decaying
Slide 1-13
Half-lives of radon
and its decay products
Radon-222
3.8 days
Polonium-218
Lead-214
3.1 minutes
26.8 minutes
Bismuth-214
19.7 minutes
Polonium-214
Lead-210
160 microseconds
22.6 years
Slide 1-14
Summary
Radon is an element with these characteristics
•
•
•
•
No
No
No
No
color
smell
taste
electrical charge
See handout 1-2
•
•
•
•
Gas
Radioactive
Naturally occurring
Does not readily react
chemically
• Harmful to human
health
Slide 1-15
Questions?
Slide 1-16
Check
your understanding
• See handout 1-3
Slide 1-17