Mass number, atomic number and isotopes

Uranium‑239 is an isotope of the element uranium.

State what is meant by the term isotopes.

Uranium‑239 can be represented using the symbol

Protons are one type of particle found in the nucleus of an atom.

How many protons are in the nucleus of an atom of uranium‑239?

Give the name of the other particle found in the nucleus of an atom of uranium‑239.

Uranium‑239 is radioactive and decays by beta emission.

Uranium‑239 has a half‑life of 23 minutes.

A sample of uranium‑239 has an initial mass of 60 g.

Calculate the mass of uranium‑239 remaining after 46 minutes.

When uranium‑239 undergoes beta decay, an isotope of the element neptunium, Np, is produced.

Which of these is the correct symbol for the neptunium nucleus produced in the beta decay of uranium‑239?

This question is about radioactivity.

The nucleus of an atom of carbon has 6 protons and 8 neutrons.

Which row of the table shows the nucleus of an atom that is a different isotope of carbon?

Which type of radiation is a high-energy electron?

A nucleus emits radiation. This causes the mass number to decrease by one. The atomic number stays the same.

Which type of radiation does the nucleus emit?

The nucleus of an isotope of uranium can be represented using this symbol.

The nucleus forms part of a positively charged ion.

How many electrons could be in this ion?

A radioactive isotope has an initial activity of 400 Bq.

The half-life of the isotope is 8 hours.

What is the activity of the isotope after 16 hours?

Which statement describes the term atomic number for a nucleus?

Which statement describes the term mass number for a nucleus?

Which statement describes the term isotopes ?

of protons

of electrons

of protons

of neutrons

An atom contains 8 protons, 8 neutrons and 8 electrons.

Which of these would result in a negatively charged ion of the same element?

It is not possible to predict exactly when a radioactive nucleus will decay.

Which feature of radioactive decay best explains this observation?

Which of these is the correct unit for measuring the activity of a radioactive sample?

A teacher uses a radioactive source containing atoms of the isotope radium-226.

Give a safety precaution that would reduce the teacher’s exposure to radiation when working with the radioactive source.

Radium-226 can be represented using the symbol

How many neutrons are in the nucleus of an atom of radium-226?

The teacher investigates the type of radiation emitted from the radioactive source.

Give the name of a piece of apparatus that detects ionising radiation.

The teacher finds that the radiation emitted from the radioactive source is not detected when the detector is more than 5 cm away from the source.

State the type of radiation emitted by the radioactive source.

The number of radium-226 atoms in the source decreases over time, with a half-life of 1600 years.

State what is meant by the term half-life.

The radioactive source contains 2.66 × 10²¹ atoms of radium-226.

Approximately how many atoms of radium-226 will remain in the source after 800 years?

Technetium-98 and technetium-99 are isotopes of the element technetium.

Describe the difference between the nuclei of technetium-98 and technetium-99

Technetium-99 is formed when the element molybdenum-99 decays.

Complete the nuclear equation for the decay of molybdenum into technetium-99

Describe an experiment that a scientist could use to demonstrate that the emission from technetium-99 is gamma radiation.

Include details of a safety precaution in your answer.

A scientist measures the count rate at different distances from the technetium source.

The graph shows how the count rate changes with distance from the technetium source.

The scientist suggests that the relationship between the count rate and distance is (distance)² × count rate constant

Use data from the graph to determine whether these results support this relationship.

The photograph shows a glass plate made from uranium glass.

Uranium oxide is used to give the glass a green colour.

State what information the numbers 92 and 238 give about the nucleus of this isotope of uranium.

Uranium‑238 decays by alpha emission.

Describe how the nucleus of a uranium‑238 atom changes as a result of alpha emission.

The table gives some information about the uranium glass plate.

Calculate the number of uranium‑238 atoms in the plate.

Uranium‑238 is an alpha emitter and has a half‑life of 4.5 billion years.

Explain why it is safe to eat food from the uranium glass plate.

Lead-210 is a radioactive isotope of lead and is represented using this symbol.

State what is meant by the term isotope.

How many protons are in the nucleus of lead-210?

A sample of lead-210 has an initial activity of 240 Bq.

After 66 years, the activity of the sample is 30 Bq.

Calculate the half-life of lead-210.