Nuclear equations

Some people used to think that radioactive substances had health benefits.

In the 1920s, a water container called a revigator was sold.

The walls of a revigator contain radioactive isotopes.

Figure 6 shows a revigator.

The revigator was filled with water and left overnight.

People then drank the water from the revigator.

The water was irradiated and contaminated by the radioactive isotopes in the walls of the revigator.

Explain how irradiating and contaminating the water affected the hazard caused by drinking the water.

A scientist tested some water that had been left in a revigator.

The water contained radon-222 and vanadium-52.

Vanadium-52 (V) decays by emitting beta particles.

What is the correct nuclear equation for this process?

Tick () one box.

Table 2 shows the half-lives of radon-222 and vanadium-52.

The scientist measured the radiation emitted by a sample of radon-222 and the radiation emitted by a sample of vanadium-52.

The scientist repeated the measurements 7.4 minutes later.

Explain how the activity of the radon-222 and vanadium-52 had changed after 7.4 minutes.

Scientists monitored the effects of drinking the water from a revigator.

Their methods and results were checked by other scientists.

What name is given to the process of other scientists checking work before it is published?

A scientist investigated the radiation emitted by different radioactive isotopes.

The scientist had a sample of polonium-210.

The radiation emitted by polonium-210 can be represented by the symbol⁴₂ He.

Which type of radiation can be represented by the symbol⁴₂ He?

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How many protons are there in a particle of radiation represented by⁴₂ He?

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A polonium-210 (Po) nucleus changes into a lead (Pb) nucleus by emitting a ⁴₂ He particle. This is shown by the following nuclear equation. 210 206 4 Po → Pb + He 84 X 2

What is the value of X ?

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The sample of polonium-210 had an activity of 100 Bq.

Complete the sentence.

Choose the answer from the box.

After one half-life, the activity of polonium-210 in the sample

The scientist investigated another radioactive isotope that is a source of gamma

radiation.

Figure 1 shows the equipment used.

The count-rate is the number of counts detected each second.

In 30 seconds the number of counts detected was 1500.

Calculate the count-rate.

The scientist placed a thick sheet of lead between the source of gamma radiation and

the detector.

What was the effect of the sheet of lead on the count-rate?

Give a reason for your answer.

The lead was irradiated by the gamma radiation.

What happened to the lead when it was irradiated by the gamma radiation?

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Gamma radiation is emitted from the nucleus of an atom.

Complete the sentence.

Choose the answer from the box.

Gamma radiation consists of.

Figure 2 shows the scientist holding the radioactive source using tongs.

Suggest one reason why using long tongs rather than short tongs was safer for the scientist.

A teacher demonstrated that the radioactive isotope americium-241 emits alpha particles.

Figure 4 shows the equipment used.

An americium-241 nucleus (Am) emits an alpha particle and turns into a neptunium nucleus (Np).

Which is the correct nuclear equation for this decay?

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What is the furthest distance that alpha radiation can travel in air?

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The teacher placed a piece of paper between the americium-241 and the radiation detector.

The reading on the count rate meter decreased by a large amount.

Why does the decreased reading show that americium-241 emits alpha radiation?

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The teacher replaced the americium-241 with a source of beta radiation.

Which symbol represents a beta particle?

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The count rate from the source was 119 ± 7 counts per second.

Calculate the smallest count rate this could have been.

A teacher investigated how the distance between a different radioactive source and the detector affects the count rate.

Draw one line from each type of variable to the description.

Figure 5 shows how the count rate from the different radioactive source changed with the distance from the source.

Describe the relationship between the distance from the source and the count rate.

A smoke detector contains a source of alpha radiation in a plastic case.

A source of beta radiation in a smoke detector would be more hazardous than a source of alpha radiation. Explain why.

Actinium (Ac) is one source of alpha radiation. An actinium (Ac) nucleus emits an alpha particle (α) and turns into a francium (Fr) nucleus. This can be represented as:

Determine the values of A and Z.

A teacher wanted to find out what nuclear radiation is emitted from a source. The teacher placed different barriers between the source and a detector. The teacher recorded the count for 30 seconds after each barrier was put in place. Table 2 shows the results.

Explain what nuclear radiation was emitted by the source.

Figure 11 shows how the activity of four different radioactive isotopes, A, B, C and D changes over time.

Write the isotopes A, B, C and D in order of increasing stability of their nuclei. Explain your answer.

Least stable Most stable

Different radioactive isotopes emit different types of nuclear radiation.

A polonium-210 (Po) nucleus emits an alpha particle (α) and turns into a lead (Pb) nucleus. This can be represented by the equation:

What is the value of A in the equation? Tick (✓) one box.

What is the value of Z in the equation? Tick (✓) one box.

A strontium-89 nucleus (Sr) emits a beta particle (β) and turns into an yttrium nucleus (Y). This can be represented by the equation:

What are the values of A and Z in the equation?

Gamma radiation is another type of nuclear radiation. What does gamma radiation consist of? Tick (✓) one box.

Explain the differences between the properties of alpha, beta and gamma radiations.

Different radioactive isotopes emit different types of nuclear radiation.

A polonium-210 (Po) nucleus emits an alpha particle (α) and turns into a lead (Pb) nucleus. This can be represented by the equation:

What is the value of A in the equation? Tick (✓) one box.

What is the value of Z in the equation? Tick (✓) one box.

A strontium-89 nucleus (Sr) emits a beta particle (β) and turns into an yttrium nucleus (Y). This can be represented by the equation:

What are the values of A and Z in the equation?

Gamma radiation is another type of nuclear radiation. What does gamma radiation consist of? Tick (✓) one box.

Explain the differences between the properties of alpha, beta and gamma radiations.

Lanthanum-140 is a radioactive isotope.

A nucleus of lanthanum-140 emits gamma radiation. What happens to the mass number and the charge of the nucleus when

Why is it difficult to detect gamma radiation?

Activity is the rate at which a radioactive source decays. A teacher measured the count-rate from a sample of lanthanum-140 using a Geiger-Muller (G-M) tube. Explain why the count rate was less than the activity of the sample of lanthanum-140

The teacher investigated how the thickness of lead affected the amount of gamma radiation that could pass through it. Figure 6 shows the apparatus.

Explain why the teacher stood as far away from the apparatus as possible.

Table 1 shows the results.

The teacher concluded that the count rate was not inversely proportional to the thickness of lead. Explain why the teacher was correct. Use the data in Table 1.

Lanthanum-140 can also emit beta radiation and change into cerium. Complete the equation showing the decay of lanthanum (La) 140 into cerium (Ce).

There are other isotopes of cerium which are radioactive. Different isotopes of cerium have different half-lives. The half-life of an isotope can be found by studying how the number of atoms changes over time. Figure 7 shows how the number of atoms of cerium-148 in a 120 g sample changes over time.

Determine the ratio of the number of cerium atoms in the sample when it was 100 seconds old compared with when the sample was 350 seconds old. Use data from Figure 7.

Determine the activity of the sample of cerium when the sample was 20 seconds old. Use Figure 7.