Specification focus questions on Radioactivity- Pearson’s Edexcel IGCSE Physics


What are protons, neutrons, and electrons and how do they contribute to the structure of an atom?

How does the atomic number relate to the protons in an atom?

What is the difference between atomic number and mass number?

What is an isotope and how does it differ from other atoms with the same element?

What are alpha (α) particles, beta (β−) particles, and gamma (γ) rays?

How can alpha, beta, and gamma rays be distinguished in terms of penetrating power and ionizing ability?

What is the effect of each type of radiation on the atomic and mass number of a nucleus?

How can nuclear equations be balanced in terms of mass and charge?

How can ionizing radiations be detected, and what is the difference between photographic film and a Geiger−Müller detector?

What are the sources of background (ionizing) radiation from Earth and space?

How is the activity of a radioactive source measured and what is the unit of measurement?

What is the half-life of a radioactive isotope and how does it differ for different isotopes?

How can you calculate the activity of a radioactive source using the half-life concept and graphical methods?

What are the uses of radioactivity in industry and medicine?

How does contamination differ from irradiation?

What are the dangers of ionizing radiations and how do they impact living organisms and cells?

What are the issues associated with the disposal of radioactive waste and how can the associated risks be reduced?


Protons, neutrons, and electrons are the three fundamental particles that make up the structure of an atom. Protons have a positive charge and are found in the nucleus of the atom, while electrons have a negative charge and occupy the outermost energy level. Neutrons are electrically neutral and also located in the nucleus.

The atomic number of an element is the number of protons in its nucleus and it determines the element’s identity. For example, an atom with 6 protons in its nucleus is the element carbon (C).

The mass number is the total number of protons and neutrons in an atom’s nucleus, while the atomic number only refers to the number of protons.

An isotope is a variation of an element that has the same number of protons but a different number of neutrons in its nucleus. Isotopes of the same element have the same atomic number, but different mass numbers.

Alpha (α) particles, beta (β−) particles, and gamma (γ) rays are ionizing radiations emitted from unstable nuclei in a random process. Alpha particles are positively charged particles made up of two protons and two neutrons, while beta particles are high-energy electrons. Gamma rays are high-energy photons that are emitted when a nucleus undergoes decay.

Alpha particles have low penetrating power and high ionizing ability, while beta particles have moderate penetrating power and moderate ionizing ability. Gamma rays have high penetrating power and low ionizing ability.

The emission of alpha particles decreases the atomic number of the nucleus by 2 and the mass number by 4, while the emission of beta particles increases the atomic number by 1 and does not change the mass number. The emission of gamma rays does not change either the atomic number or the mass number.

Nuclear equations can be balanced by ensuring that the number of protons and the charge are equal on both sides of the equation.

Ionizing radiations can be detected using photographic film or a Geiger-Müller detector. Photographic film records the exposure to ionizing radiation, while a Geiger-Müller detector measures the ionizing radiation by detecting the ionization it creates in a gas-filled chamber.

Background (ionizing) radiation from Earth and space can come from natural sources such as cosmic rays, radon gas, and soil.

The activity of a radioactive source is measured in becquerels and it decreases over time as the radioactive isotopes decay.

The half-life of a radioactive isotope is the time it takes for half of the original amount of the isotope to decay. Different radioactive isotopes have different half-lives.

The activity of a radioactive source can be calculated using the half-life concept and graphical methods. The activity can be determined by measuring the rate at which the radioactive isotopes decay over time.

Radioactivity has many uses in industry and medicine, including radiation therapy for cancer treatment, food irradiation to reduce pathogens, and in the production of medical isotopes for imaging and diagnostic procedures.

Contamination refers to the presence of radioactive material on a surface or in the environment, while irradiation refers to the exposure to ionizing radiation.

Ionizing radiations can cause mutations in living organisms, damage cells and tissues, and pose a risk for the disposal of radioactive waste. The associated risks can be reduced through proper handling and disposal procedures, as well as protective measures for workers and the public.

The issues associated with the disposal of radioactive waste include potential harm to human health and the environment due to the release of radioactive material. To reduce these risks, methods such as deep geological disposal, secure storage and proper transport, and treatment and conditioning of waste can be implemented. Additionally, the use of protective measures such as barriers and isolation from the biosphere can also reduce the risks associated with the disposal of radioactive waste.


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