Chapter 25 Nuclear Chemistry
25.4 Radiation in Your Life
Chemistry
Today we are learning to:1. Identify 3 devices used to detect radiation
2. Describe how radioisotopes are used in medicine
25.4
Radiation in Your Life
In a smoke detector, radiation from
the Americium nuclei ionizes the
nitrogen and oxygen in smoke-free
air, allowing a current to flow.
When smoke particles get in the
way, a drop in current is detected
by an electronic circuit, causing it
to sound an alarm. You will learn
about some of the other practical
uses of radiation.
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Radiation in your life
Detecting Radiation
Radiation emitted by radioisotopes is called ionizing radiation
It has enough energy to knock electrons off some atoms of the bombarded
substance to produce ions.
Geiger counters, scintillation counters, and film badges are commonly used
to detect radiation.
25.4
Detecting Radiation Radiation in your life
Detecting Radiation
Radiation can produce ions, which can then be detected, or it can expose a
photographic plate and produce images.
25.4
Detecting Radiation Radiation in your life
Detecting Radiation
1. Geiger Counter: uses a gas-filled metal tube to detect radiation. It is
usually used for detecting beta radiation
25.4
Detecting Radiation Radiation in your life
Detecting Radiation
2. Scintillation Counter: uses a phosphor-coated surface to detect radiation.
It can detect all types of ionizing radiation
25.4
Detecting Radiation Radiation in your life
Detecting Radiation
3. Film Badge: consists of several layers of photographic film covered with
black lightproof paper, all encased in a plastic or metal holder.
25.4
Detecting Radiation Radiation in your life
Using Radiation
Neutron activation analysis is a procedure used to detect trace amounts
of elements in samples.
Neutron activation analysis is used by museums to detect art forgeries, and
by crime laboratories to analyze gunpowder residues.
25.4
Detecting Radiation Radiation in your life
Using Radiation
Radioisotopes in medicine
Radioisotopes can be used to diagnose medical problems and, in some
cases, to treat diseases.
Iodine-131 is used to detect thyroid gland problems
25.4 Section Quiz.
1. Ionizing radiation can remove _______ from
atoms.
a.
b.
c.
d.
protons
neutrons
positrons
electrons.
25.4 Section Quiz.
2. Which of the following is NOT a device used
to detect radiation?
a.
b.
c.
d.
Geiger counter
scintillation counter
film badge
radioisotope
25.4 Section Quiz.
3. Choose the correct words for the space.
When a tumor is treated by radiation, more
cancer cells than normal cells are killed
because cancer cells ____________ than
normal cells.
a. are more susceptible to damage because they
grow faster
b. absorb more radiation because they are larger
c. grow slower
d. are smaller
25.4 Section Quiz.
– 4.
How do scientists detect thyroid
problems?
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with teletherapy
by neutron activation analysis
using an iodine-131 tracer
using a radioisotope sealed in a gold tube
2.3 Vocabulary 25.3 Vocabulary
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•
Fission: the splitting of a nucleus into smaller fragments
Neutron moderation: process of slowing down neutrons do they will be
absorbed by nuclei.
Neutron absorption: process of decreasing the number of slow moving
neutrons by using control rods
Fusion: when light nuclei fuse together to form a single nuclei
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25.4 Vocabulary
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Ionizing Radiation: knocks electrons of atoms to produce ions
Geiger Counter
Scintillation Counter
Film badge
Neutron activation analysis: used to detect trace amounts of elements in a
sample
END OF SHOW