Science Double Award - 4SD0 PearsonEdexcel

Radioactivity

Gbogbo ọrọ náà

Radioactivity is the spontaneous emission of radiation from unstable atomic nuclei. It underpins everything from medical imaging and cancer treatment to smoke detectors and carbon dating.

In this lesson you will learn about atomic structure, isotopes, the three types of nuclear radiation (alpha, beta and gamma), how to balance nuclear equations, half-life calculations, uses and dangers of radiation, and the difference between contamination and irradiation.

Ebumnobi

Describe the structure of an atom in terms of protons, neutrons and electrons and use standard notation to describe particular nuclei
Know the terms: atomic (proton) number, mass (nucleon) number and isotope
Know that alpha particles, beta particles and gamma rays are ionising radiations emitted from unstable nuclei in a random process
Describe the nature of alpha particles, beta particles and gamma rays and recall that they may be distinguished in terms of penetrating power and ability to ionise
Investigate the penetration powers of different types of radiation
Describe the effects on the atomic and mass numbers of a nucleus of the emission of each of the four main types of radiation
Understand how to balance nuclear equations in terms of mass and charge
Know that photographic film or a Geiger-Muller detector can detect ionising radiations
Explain the sources of background (ionising) radiation from Earth and space
Know that the activity of a radioactive source decreases over a period of time and is measured in becquerels
Know the definition of the term half-life and understand that it is different for different radioactive isotopes
Use the concept of half-life to carry out simple calculations on activity, including graphical methods
Describe uses of radioactivity in industry and medicine
Describe the difference between contamination and irradiation
Describe the dangers of ionising radiations, including mutations, cell damage and radioactive waste disposal

Akọmọ Ojú-ẹkọ

Most atoms are perfectly stable. But some have nuclei with an imbalance of protons and neutrons that makes them unstable. These atoms release energy by emitting radiation in a process that is entirely random and cannot be predicted for any individual nucleus.

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Budata ngwa Green Bridge CBT na ekwentị maọbụ kọmputa gị iji nweta akwụkwọ ndụmọdụ zuru oke, ajụjụ mmụta, na ndị ọzọ.

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Ayẹwo Ẹkọ

Ekele diri gi maka imecha ihe karịrị na Radioactivity. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.

Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.

Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.

Alpha particles are stopped by: A) Concrete B) Aluminium C) Paper D) Nothing Answer: C
In beta decay, the atomic number: A) Decreases by 2 B) Stays the same C) Increases by 1 D) Decreases by 1 Answer: C
The most ionising radiation is: A) Alpha B) Beta C) Gamma D) X-rays Answer: A
Half-life is the time for: A) All atoms to decay B) Activity to reach zero C) Activity to halve D) Temperature to halve Answer: C
Contamination differs from irradiation because: A) It involves gamma only B) Radioactive material is on/in the body C) It does not involve radiation D) It stops when the source is removed Answer: B