7.14 describe the dangers of ionising radiations and describe how the associated risks can be reduced.

Radiation can cause mutations in living organisms: radiation can damdge the stucture of a cells DNA, when the cell replicates the changes (mutation) will be passed on; this can be how cancer is caused.

Radiation can damage cells and tissue: atoms can be change by radiation, this prohibits them functioning properly, this can mean cells and so tissue are damaged.

The problems arising in the disposal of radioactive waste: this waste emits radiation that, as shown above, can be dangerous. If the waste is put into water it can poison ecosystems, similarly with land. Radioactive waste tends to be buried under the ground; with the thinking that when it is much less harmful it can be dug up and disposed of.

7.13 describe the uses of radioactivity in medical and non-medical tracers, in radiotherapy, and in the radioactive dating of archaeological specimens and rocks

Tracers- a radioactive source is put into a system (like a piping network), it will build up where there is a blockage a be detected, showing where a problem is.

Medical tracers- a radioactive source is put into a body and will build up at a blockage so an area of problem can be detected.

Radiotherapy- radiation is used to destroy unwanted cells (cancerous cells.)

Radioactive dating- aka carbon dating. The amount of radiation from an object is measured, the half life of the carbon is then used to see how old the object is. Archaeologists use this to tell the age of an object.

7.12 use the concept of half-life to carry out simple calculations on activity

Some people use equations to work out half life calculations, but you don't really need to. Make sure that you understand that half life is the time taken for the amount of radiation emitted to half; two half lives is the amount of time taken for the value to half twice (ect.)

The papers often contain half life graphs to interpret. Draw a line from half the value of the start point to the curve, draw down to the bottom line and you will get your half life. If you are doing this in an exam the mark scheme sometimes requires that you make it clear you were halfing the start number.. odd but there we go.

gcsescience

7.11 understand the term ‘half-life’ and understand that it is different for different radioactive isotopes

A half-life is the time it takes for the radiation emitted by a source to decrease by half.
Half-lives are different for different sources of radiation.

7.10 understand that the activity of a radioactive source decreases over a period of time and is measured in becquerels

The radiation emitted by a radioactive source will decrease over time. Radiation is measured in becquerels.

7.9 explain the sources of background radiation

There are so many sources of background radiation: different radioactive materials are in the environment.
An example of this is boron in the soil which emits radiation; cosmic rays from space are radioactive too.

bbc

7.8 understand that ionising radiations can be detected using a photographic film or a Geiger-Muller detector

Radiation imprints on camera film.

A Geiger-Muller detector (or GM counter) beeps in the presence, the more radiation the more frequent the beeps.

7.7 understand how to complete balanced nuclear equations

Nuclear equations show the atoms atomic number and atomic mass on one side and the radiation (with mass and number) and the new element (with mass and number.)

For example, uranium has experienced alpha decay:

thinkquest

Here lithium has experienced beta decay:

hk-phy.org

7.6 describe the effects on the atomic and mass numbers of a nucleus of the emission of each of the three main types of radiation

Alpha makes an atom go down 2 on its atomic number and four on its atomic mass: it will change to the element with a the atomic number 2 less than it was.

When beta radiation occurs a neutron splits into a proton and a electron, the electron is emitted from the atom, but the proton stays in the nucleus: this changes the atomic number up one, the element becomes that with the next atomic number up. The mass number remains the same as a neutron- mass 1- became a proton- mass 1.

Gamma rays have no specific effect on the atomic or mass number.

7.5 describe the nature of alpha and beta particles and gamma rays and recall that they may be distinguished in terms of penetrating power

alpha particles are two neutrons and two protons; also known as a helium nucleus. Alpha particles could not penetrate a piece of paper if they tried.

Beta particles are electrons, they are emitted when a neutron turns into a proton and an electron. It won't penetrate aluminium.

Gamma rays are a type of electromagnetic wave, they are often emitted alongside the other types of radiation. Gamma cannot penetrate lead.

7.4 understand that alpha and beta particles and gamma rays are ionising radiations emitted from unstable nuclei in a random process

alpha particles, beta particles and gamma rays are all types of radiation.
The term ionising means they damage cells.
Radiation is emitted from the nucleus of an atom that is unstable (in a way it is too full and trying to off load.)

7.2 describe the structure of an atom in terms of protons, neutrons and electrons and use symbols such as 14C 6 to describe particular nuclei

Protons (+) and neutrons are in the nucleus of an element. Electrons (-) orbit on shells (or orbitals.)

7.3 understand the terms atomic (proton) number, mass (nucleon) number and isotope

The atomic mass of an element (the number written above an elements symbol) is the number of protons + the number of neutrons.

The atomic number is the number of protons. This will equal the number of electrons in an element.

An isotope of an element is one with the same configuration of protons and electrons but a different amount of neutrons.

wyzant