Nuclear equations

There are different isotopes of the element carbon.

When carbon-14 decays into nitrogen-14, it emits beta radiation.

Complete the equation for the decay of carbon-14.

Carbon-14 has a half-life of 5700 years.

Explain what half-life means.

Alpha particles, beta particles, and gamma rays can penetrate different types and thicknesses of material.

Draw one line from each type of radiation to the type and maximum thickness of material radiation is able to penetrate.

Type of radiation
Type and maximum thickness of material

When uranium‑238 decays, it forms isotopes of different elements.

The graph shows part of the decay chain produced when uranium‑238 decays.

Circle two points on the graph which are isotopes of the same element.

Explain how you worked out your answer.

(b) Describe what happens to the atomic number and mass of a nucleus of²³⁴Th as it decays into (i) ²³⁴Pa.

Which type of radiation is emitted when²³⁴Th decays into²³⁴Pa? (ii)

Eventually the isotope²⁰⁶Pb is formed and the decay chain stops. (d)

Explain why the decay chain stops at²⁰⁶Pb.

When an alpha particle hits a beryllium nucleus, a particle ‘X’ is emitted.

What is the missing number, labelled n in the equation?

A –1

B 0

C 1

D 2

In 1986, a nuclear power station exploded in Chernobyl.

The radioactive isotopes caesium-137 (Cs-137) and iodine-131 (I-131) were released.

An old unit of activity is the Curie (Ci).

• The activity of Cs-137 released in the explosion was 2 300 000 Ci.

• 1 Ci = 37 000 000 000 Bq

Calculate the activity of Cs-137 released in Bq. Give your answer in standard form.

Cs-137 emits beta radiation. The table shows some information about this decay.

Use the table to complete the balanced nuclear equation for Cs-137 decay.

*(c) The isotopes I-131 and Cs-137 from Chernobyl contaminated sheep.

The government stopped the movement of contaminated sheep for 26 years.

• If the activity per kilogram of sheep was greater than 1000 Bq / kg, the sheep were contaminated.

• In 1986, the activity per kg of some sheep was greater than 1600 Bq / kg.

• I-131 emits beta radiation.

• Cs-137 emits beta and gamma radiation.

The graphs show how the amount of I-131 and Cs-137 change with time:

Graph for I-131

Graph for Cs-137

Use the graphs to explain why the government stopped the movement of contaminated sheep for 26 years.

Use ideas about half-life and half-life calculations.

This question is about radioactive atoms.

Why are some atoms radioactive?

Phosphorus-32 (³²₁₅P) gives out beta particles.

Complete the equation for the beta decay........

Phosphorus-32 only gives out beta particles.

Describe a simple experiment to show how this can be demonstrated in a laboratory.

You may include a diagram in your answer.

Beta particles are one type of radioactive particle.

Name a different particle given out by radioactive atoms.

Look at the diagram. It compares the model of the atom today with a model of the atom in 1902.

Model of the atom today
Model of the atom in 1902

Describe two differences between the models in the diagram.

Explain why the model of the atom has changed over time.

This question is about nuclear radiation.

Q and R are different radioactive isotopes. Q has a different half-life to R.

Explain what is meant by the term half-life.

The graph shows how activity of isotope Q and isotope R change with time.

Which isotope, Q or R, has the longest half-life? Explain your answer.

The table shows information about different elements.

Iodine-131 is a radioactive isotope. Iodine-131 decays, emitting a beta () particle.

Write a balanced nuclear equation for iodine-131 decay. The first part is done for you.

The table shows how the activity of iodine-131 decreases with time.

Use your answer to (c)(i) to calculate the half-life of iodine-131.