Alpha Radiation as a Helium Nucleus, Beta Radiation as a High Energy Nucleon and Gamma Radiation as Electromagnetic

Alpha, Beta, and Gamma Radiation Characteristics:

Alpha Radiation: This is emitted by some radioactive substances. It is a helium nucleus, made up of 2 protons and 2 neutrons.
Beta Radiation: Consists of high-energy electrons or positrons. It is a high speed, high energy nucleon ejected from the nucleus.
Gamma Radiation: Unlike alpha and beta, gamma radiation is electromagnetic. It is similar to X-rays but has more energy.

Differences Based on Penetration and Ionising Power:

Alpha Particles: Their large size and charge mean they are highly ionising. They have a low penetration power and can be stopped by a sheet of paper or a few centimetres of air.
Beta Particles: They are less ionising than alpha particles and more penetrating. They can be stopped by a sheet of aluminium or several metres of air.
Gamma Rays: They are the least ionising but the most penetrating. They can pass through the human body and need several centimetres of lead or a metre of concrete to stop them.

Effects on Atomic Structure:

Alpha Decay: An atom emitting an alpha particle has its atomic number reduced by 2 and mass number by 4.
Beta Decay: Occurs when a neutron changes into a proton and an electron. The electron is ejected as a beta particle, increasing the atomic number by 1 but no change in mass number.
Gamma Decay: This generally occurs to get rid of excess energy from the nucleus after alpha or beta decay. There is no change in atomic or mass number.

Detection and Uses:

Alpha Particles: Used in smoke detectors. Weak alpha radiation ionises air particles. When the smoke particles interfere with this, the drop in current triggers the alarm.
Beta Particles: Used in paper, film, and metal sheeting thickness monitoring.
Gamma Rays: In Sterilising medical equipment and food, and in cancer radiotherapy.

Remember, knowledge of these points and understanding how they link together can help answer many questions on the topic. Practice questions to ensure you understand the concepts and can apply them in different scenarios.