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.
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Chapter 25 Nuclear Chemistry 25.4 Radiation in Your Life
Chemistry Today we are learning to:-1. Identify 3 devices used to detect radiation2. 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. http://www.periodicvideos.com/
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 Radiation in your life Detecting Radiation Detecting Radiation • Radiation can produce ions, which can then be detected, or it can expose a photographic plate and produce images.
25.4 Radiation in your life Detecting Radiation Detecting Radiation • Geiger Counter: uses a gas-filled metal tube to detect radiation. It is usually used for detecting beta radiation
25.4 Radiation in your life Detecting Radiation Detecting Radiation • Scintillation Counter: uses a phosphor-coated surface to detect radiation. It can detect all types of ionizing radiation
25.4 Radiation in your life Detecting Radiation Detecting Radiation • Film Badge: consists of several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder.
25.4 Radiation in your life Detecting Radiation Using Radiation • Neutron activation analysisis 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 Radiation in your life Detecting Radiation 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. • protons • neutrons • positrons • electrons.
25.4 Section Quiz. 2. Which of the following is NOT a device used to detect radiation? • 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. • are more susceptible to damage because they grow faster • absorb more radiation because they are larger • grow slower • are smaller
25.4 Section Quiz. • 4. How do scientists detect thyroid problems? • 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 • 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 25.4 Vocabulary • 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