Radioactivity Warm-Up, Instruction, Assignment, and Quiz

how many grams of carbon will remain after 2.5 seconds have elapsed?

50

A 60-g sample of radioactive isotope is measured after two half-lives have passed. What pair of percentages describes the sample after two half-lives? 50% unchanged and 50% stable 25% unchanged and 75% stable 12.5% unchanged and 87.5% stable 75% unchanged and 25% stable

B. 25% unchanged and 75% stable

Lead-202 has a half-life of 53,000 years. How long will it take for 15/16 of a sample of lead-202 to decay? 106,000 years 159,000 years 212,000 years 265,000 years

C. 212,000 years

Matilda has a 100 g rock sample. She knows that the rock contains uranium-238 and that the half-life of uranium-238 is 4.5 × 109 years. If she cuts the rock sample in half, what happens to the half-life of the uranium? The half-life increases. The half-life decreases. The half-life remains the same.

D. The half-life remains the same.

Which is not a form of ionizing radiation? ultraviolet light gamma rays X-rays infrared light

D. infrared light

The graph shows all of the stable isotopes of elements according to the numbers of protons and neutrons in their nuclei. Which statements are supported by the graph? Check all that apply. For large atoms, more neutrons than protons are needed to be stable. Nuclei that have 90 or greater protons are always radioactive. Atoms must have equal numbers of protons and neutrons to be stable. Atoms that have less than 10 protons do not need neutrons to be stable.

1, & 2

Which statements accurately relate radiation and health? Check all that apply. Ionizing radiation produces ions that disrupt natural chemical reactions in the body. Stochastic effects are associated with short-term, high-level exposure to radiation. Cancer and DNA mutations are examples of non-stochastic effects. A single X-ray delivers about 1/10 of the radiation exposure permitted for one person per year. Lead shielding is an effective means of reducing radiation exposure.

1, 4, & 5

A sample of radium-226 will decay to ¼ of its original amount after 3200 years. What is the half-life of radium-226? years

1,600

how many grams will remain after 7.5 seconds?

12.5

The half-life of plutonium-238 is 87.7 years. What percentage of the atoms in a sample of plutonium-238 will remain radioactive after 263.1 years? % What percentage of the atoms in the same sample of plutonium-238 will have changed to a stable isotope after 263.1 years? %

12.5 87.5

how many grams will remain after 5 seconds?

25

What is the mass number of the isotope lithium-7? Lithium has 3 protons. How many neutrons are in the isotope lithium-8?

7 5

Which describes why radioisotopes can be used as tracers in studying the biological and chemical processes of plants? The radioisotope is chemically identical to the nonradioisotope the plant normally uses. The radioisotope is absorbed more quickly than the nonradioisotope the plant normally uses. The radioisotope converts the nonradioisotope normally used by a plant into a radioisotope. The radioisotope travels through the plant without participating in any chemical processes.

A. The radioisotope is chemically identical to the nonradioisotope the plant normally uses.

Drag and drop each description into the appropriate category Alpha decay Beta decay Gamma decay

Alpha decay: cannot penetrate paper emits alpha particle Beta decay: penetrates paper, not foil emits electron or positron Gamma decay: requires thick lead shield emits photon

When does the radioactive decay of a radioisotope stop? Give one example.

An unstable isotope continues the decay process until it reaches a stable form. One example is the decay of carbon-14 to nitrogen-14.

The half-life of carbon-14 is 5730 years. How long will it take for 7/8 of a sample of carbon-14 to decay? 11,460 years 17,190 years 22,920 years 28,650 years

B. 17,190 years

The table lists several radioisotopes that have technological uses. Which radioisotope would be used by both archaeologists and botanists (scientists who study plants)? uranium-238 carbon-14 iodine-131 technetium-99

B. carbon-14

Gertrude writes a short story in which the main character must enter a nuclear-powered spaceship's engine room that has lost its shielding in order to prevent the engine from flooding the rest of the ship with radiation. The main character is not wearing protective gear. What effects are best for Gertrude to consider when planning what may happen to the character? non-stochastic effects such as possible DNA mutations later in life resulting from the short-term, high-level exposure non-stochastic effects such as severe burns and radiation sickness resulting from the short-term, high-level exposure stochastic effects such as possible DNA mutations that are unlikely to occur from the single, low-level exposure stochastic effects such as severe burns and radiation sickness resulting from the long-term, low-level exposure

B. non-stochastic effects such as severe burns and radiation sickness resulting from the short-term, high-level exposure

Read each statement and determine if it describes alpha, beta, or gamma decay. decay occurs when a nucleus emits either an electron or a positron. Gamma decay has no charge or mass but is capable of penetrating many substances. decay has a charge of +2. decay results in a new element with the same mass number. decay can be stopped by a piece of paper.

Beta Gamma Alpha Beta Alpha

Carlos arranges his notes about radioactive decay in a graphic organizer. He wants to add the labels shown. Label 1: Photon Label 2: Positron Label 3: No change in mass number Which is the best region for each label? Label 1: Z Label 2: X Label 3: Y Label 1: X Label 2: Z Label 3: X Label 1: X Label 2: Z Label 3: Y Label 1: X Label 2: Z Label 3: Z

C. Label 1: X Label 2: Z Label 3: Y

Which statement accurately describes the use of radioactive decay? Technetium-99 is used as a radioactive tracer because it remains in the body for a long time. Some types of cancer cells are killed by directing alpha rays at the tumor from outside the body. Plants utilize radioisotopes in the same way they use non-radioisotopes because they are chemically identical. Geologists and archaeologists use different dating processes to determine the age of rocks, fossils, and ancient artifacts.

C. Plants utilize radioisotopes in the same way they use non-radioisotopes because they are chemically identical.

Which characteristics of a radioisotope make it useful for diagnosing medical problems? a long half-life and it is taken up by a specific part of the body a long half-life and it is not taken up by the body a short half-life and it is taken up by a specific part of the body a short half-life and it is not taken up by the body

C. a short half-life and it is taken up by a specific part of the body

What did the accident at the nuclear power plant in Chernobyl in 1986 demonstrate about the use of nuclear power that had not been previously demonstrated? The byproducts of the process are radioactive. The generation of electricity releases no carbon dioxide. The uranium fuel that is used is radioactive. Large areas can be contaminated with radiation.

D. Large areas can be contaminated with radiation.

What is ionizing radiation, and why is it harmful? Give at least one example.

Ionizing radiation is a type of radiation that can break molecules into ions. These ions can disrupt the natural chemical reactions in the body and damage living cells. Examples of ionizing radiation include ultraviolet (UV) radiation in sunlight, X-rays used in medical imaging, and gamma rays produced by radioactive materials.

Describe at least one technological application of radioactive decay that can benefit human health.

Radioisotopes are used in medicine as tracers to detect and diagnose medical problems. Radioisotopes are also used in radiation therapy to treat cancer.

Archaeologists use radioactive decay of an isotope of the element because it has a fairly short half-life and is found in anything that was once living.

carbon

Complete the statement with the correct term. As the size of the nucleus increases, more are needed to maintain the attractive force.

neutrons

place the tiles in the correct order to describe how a nuclear power plant generates power.

radioactive decay produces heat boiling water produces steam steam spins turbines electricity is generated

Match each key term with the correct definition radioisotope radioactivity radioactive decay strong nuclear force

radioisotope: an atom with an unstable nucleus radioactivity: the spontaneous discharge of energy from an unstable nucleus radioactive decay: the process by which the nucleus of an unstable isotope changes strong nuclear force: binds protons and neutrons together in the nucleus