Physics - Types of radiation Flashcards
What is the structure of an atom?
Atoms contain three sub-atomic particles called protons, neutrons and electrons. The protons and neutrons are found in the nucleus at the centre of the atom. The electrons are arranged is shells around the nucleus.
What happens when atoms lose/gain electrons?
-if an atom loses one or more electrons, it becomes a positively charged ion
-if an atom gains one or more electrons, it becomes a negatively charged ion
What is the atomic number (bottom)?
The atomic number (Z) of an atom is the number of protons it contains. All the atoms of a particular element have the same proton number. The amount of protons in an atom is the same as the electrons.
What is the mass number (top)?
The nucleon number (or mass number) of an atom is the total number of protons and neutrons it contains. The nucleon number of an atom is never smaller than the proton number. It can be the same, but is usually bigger.
What are isotopes?
Isotopes are the atoms of an element with different numbers of neutrons. They have the same atomic number, but different mass numbers.
What are the three main types of ionising radiation emitted from unstable nuclei?
alpha, beta and gamma radiation
What is ionising radiation?
Radiation that is able to remove electrons from atoms or molecules to produce positively charged particles called ions.
What are alpha particles?
Subatomic particle comprising two protons and two neutrons (the same as a helium nucleus).
What is beta radiation?
Beta radiation consists of high-energy electrons emitted from the nucleus. These electrons have not come from the electron shells or energy levels around the nucleus. Instead, they form when a neutron splits into a proton and an electron. The electron then shoots out of the nucleus at high speed, leaving the new proton behind in the nucleus.
What is gamma radiation?
Gamma radiation is very short wavelength, high frequency electromagnetic radiation. This is similar to other types of electromagnetic radiation, such as visible light and X rays, which can travel long distances.
What is low level nuclear waste and how can it be disposed?
Contaminated equipment, materials and protective clothing
Disposed of in drums and surrounded by concrete, and in clay-lined landfill sites
What is intermediate level nuclear waste and how can it be disposed?
-Components from nuclear reactors, radioactive sources used in medicine or research
-Mixed with concrete and put in a stainless steel drum in a purpose-built store
What is high level nuclear waste and how can it be disposed?
-Used nuclear fuel and chemicals from reprocessing fuels
-Stored underwater in large pools for 20 years, then placed in storage casks in purpose-built underground stores where air can circulate to remove the heat produced. High-level waste decays into intermediate-level waste over many thousands of years.
What are natural sources of background radiation?
- cosmic rays - radiation that reaches the Earth from space
- rocks and soil - some rocks are radioactive and give off radioactive radon gas
- living things - plants absorb radioactive materials from the soil and these pass up the food chain
What are artificial sources of background radiation?
- Medical X-rays
- Nuclear missiles
- Nuclear power
