Changes

| style="height:20px; width:400px; text-align:left;" |[[Alpha Particle|Alpha particles]] can travel around 5cm 15cm through [[air]] ([[STP]]) before [[colliding]] with and [[ionising]] [[atom]]s or [[molecule]]s.

<math>{}_Z^AX \rightarrow {}_{Z-2}^{A-4}Y + {}_2^4\alpha</math>

<math>_{92}^{238}U \rightarrow _{90}^{234}Th + _2^4\alpha</math>====Example Calculations==== {| class="wikitable"|-| style="height:20px; width:300px; text-align:center;" |'''Find the [[element]] 'X' and calculate its [[Relative Atomic Mass|relative atomic mass]] 'A' and its [[Relative Atomic Charge|relative atomic charge]] 'Z'.''' <math>{}_{84}^{210}Po \rightarrow {}_{Z}^{A}X + {}_2^4\alpha</math> | style="height:20px; width:300px; text-align:center;" |'''Find the [[element]] 'X' and calculate its [[Relative Atomic Mass|relative atomic mass]] 'A' and its [[Relative Atomic Charge|relative atomic charge]] 'Z'.''' <math>{}_{Z}^{A}X \rightarrow {}_{86}^{222}Rn + {}_2^4\alpha</math> |-| style="height:20px; width:300px; text-align:left;" |'''1. Calculate the [[Relative Atomic Mass|relative atomic mass]] by looking at the top row of numbers.''' 210 = A + 4 A = 206| style="height:20px; width:300px; text-align:left;" |'''1. Calculate the [[Relative Atomic Mass|relative atomic mass]] by looking at the top row of numbers.''' A = 222 + 4 A = 226|-| style="height:20px; width:300px; text-align:left;" |'''2. Calculate the [[Relative Atomic Charge|relative atomic charge]] by looking at the bottom row of numbers.''' 84 = Z + 2 Z = 82| style="height:20px; width:300px; text-align:left;" |'''2. Calculate the [[Relative Atomic Charge|relative atomic charge]] by looking at the bottom row of numbers.''' Z = 86 + 2 Z = 88|-| style="height:20px; width:300px; text-align:left;" |'''3. Since the [[Relative Atomic Charge|relative atomic charge]] is the same as the [[Atomic Number|atomic number]] look up the [[element]] on the [[Periodic Table|periodic table]].''' <math>{}_{82}^{206}Pb</math>| style="height:20px; width:300px; text-align:left;" |'''3. Since the [[Relative Atomic Charge|relative atomic charge]] is the same as the [[Atomic Number|atomic number]] look up the [[element]] on the [[Periodic Table|periodic table]].''' <math>{}_{88}^{226}Ra</math>|} ===References=======AQA====:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Alpha decay, pages 109, 112-3, 116, GCSE Physics; Student Book, Collins, AQA']:[https://www.amazon.co.uk/gp/product/1782946403/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946403&linkCode=as2&tag=nrjc-21&linkId=32a0abb60dff015b15b50e9b1d7b4644 ''Alpha particle scattering experiment, pages 108, 109, GCSE Combined Science Trilogy; Physics, CGP, AQA']:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Alpha particle scattering experiment, pages 120, 121, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA']:[https://www.amazon.co.uk/gp/product/0008158762/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158762&linkCode=as2&tag=nrjc-21&linkId=a0fffa35b3ea49a63404f6704e0df7cc ''Alpha particle, page 21, GCSE Chemistry; Student Book, Collins, AQA']:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Alpha particle, pages 109, 112-6, 132-3, GCSE Physics; Student Book, Collins, AQA']:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Alpha particle; scattering experiment, pages 132-3, GCSE Physics; Student Book, Collins, AQA']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Alpha particles, page 94, GCSE Physics, Hodder, AQA']:[https://www.amazon.co.uk/gp/product/1782946403/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782946403&linkCode=as2&tag=nrjc-21&linkId=32a0abb60dff015b15b50e9b1d7b4644 ''Alpha particles, pages 114, 116, 122, GCSE Combined Science Trilogy; Physics, CGP, AQA']:[https://www.amazon.co.uk/gp/product/1782945970/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945970&linkCode=as2&tag=nrjc-21&linkId=a120d24dcc7cc7a58192069a3aafc1d2 ''Alpha particles, pages 126, 128, 134, GCSE Physics; The Complete 9-1 Course for AQA, CGP, AQA']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Alpha particles, pages 344, 345, GCSE Combined Science Trilogy 1, Hodder, AQA']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Alpha particles; effects on the body, page 102, GCSE Physics, Hodder, AQA']:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Alpha particles; properties of, pages 346, 347, GCSE Combined Science Trilogy 1, Hodder, AQA']:[https://www.amazon.co.uk/gp/product/1471851370/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851370&linkCode=as2&tag=nrjc-21&linkId=01c69b0ae058f809cf636033e6ba793e ''Alpha particles; properties of, pages 96, 97, GCSE Physics, Hodder, AQA']:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe09670 ''Alpha radiation, pages 198, 199, GCSE Combined Science; The Revision Guide, CGP, AQA']:[https://www.amazon.co.uk/gp/product/178294558X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294558X&linkCode=as2&tag=nrjc-21&linkId=f0dfb66dafcb0c6e9449e7b1a4ae1ac11 ''Alpha radiation, pages 43-45, 47, GCSE Physics; The Revision Guide, CGP, AQA']:[https://www.amazon.co.uk/gp/product/019835939X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=019835939X&linkCode=as2&tag=nrjc-21&linkId=57e96876985fc39b1a3d8a3e3dc238b6 ''Alpha radiation, pages 92-93, 96, 98-99, 109, GCSE Physics; Third Edition, Oxford University Press, AQA']:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe09671 ''Alpha radiation; dangers, page 201, GCSE Combined Science; The Revision Guide, CGP, AQA']====Edexcel====:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Alpha decay, pages 156-159, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Alpha decay; dangers, pages 165, 166, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Alpha decay; uses, pages 168, 171, 172, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Alpha particles, page 362, GCSE Combined Science, Pearson Edexcel '']:[https://www.amazon.co.uk/gp/product/1292120223/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120223&linkCode=as2&tag=nrjc-21&linkId=068ecf40278c32406a7f1c6e66751417 ''Alpha particles, page 98, GCSE Physics, Pearson Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Alpha particles, pages 156, 157, GCSE Physics, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945741/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945741&linkCode=as2&tag=nrjc-21&linkId=30da4f2178da182547b62a7329d13b57 ''Alpha particles, pages 174, 175, GCSE Combined Science; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782945733/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945733&linkCode=as2&tag=nrjc-21&linkId=2a2dbec9db6bf5766c0458d908fa0a52 ''Alpha particles, pages 51, 52, GCSE Physics; The Revision Guide, CGP, Edexcel '']:[https://www.amazon.co.uk/gp/product/1782948163/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948163&linkCode=as2&tag=nrjc-21&linkId=0fdbfd5dd397d6e24a9dfb250f08587f ''Alpha particles; scattering experiment, pages 149, 150, GCSE Physics, CGP, Edexcel ''] ====OCR==== :[https://www.amazon.co.uk/gp/product/0198359837/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359837&linkCode=as2&tag=nrjc-21&linkId=3c4229e8b023b2b60768e7ea2307cc6f ''Alpha particles, pages 20, 172-174, Gateway GCSE Physics, Oxford, OCR '']:[https://www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Alpha radiation, pages 197, 198, 200, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR '']:[https://www.amazon.co.uk/gp/product/1782945687/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945687&linkCode=as2&tag=nrjc-21&linkId=9a598e52189317a20311d7a632747bc9 ''Alpha radiation, pages 74-76, 78, 79, Gateway GCSE Physics; The Revision Guide, CGP, OCR ''] ==Key Stage 5=====Meaning===An '''alpha particle''' ('''α-particle''') is a type of [[Ionising Radiation|ionising radiation]] made of 2 [[proton]]s and 2 [[neutron]]s [[emit]]ted from the [[Atomic Nucleus|nucleus]] of an [[Unstable Isotope|unstable isotope]]. ===About Alpha Particles===: '''Alpha particles''' may also be referred to as '''alpha radiation''' and is written with the symbol '''α'''.: '''Alpha particles''' are a [[Helium]] [[Atomic Nucleus|nucleus]].: '''Alpha particles''' have a [[Relative Atomic Mass|relative atomic mass]] of 4 and [[Relative Atomic Charge|relative charge]] of +2.: '''Alpha particles''' are [[emit]]ted when a [[Atomic Nucleus|nucleus]] is too large or the [[ratio]] of [[proton]]s to [[neutron]]s is too large.: '''Alpha particles''' are [[emit]]ted rather than single [[proton]]s or [[neutron]]s because the [[Helium]] [[Atomic Nucleus|nucleus]] is extremely [[Stable Isotope|stable]]. ====Charge and Mass===={| class="wikitable"|-|[[File:AlphaParticleCharge.png|center|200px]]| style="height:20px; width:400px; text-align:left;" |Scientist were able to determine the [[Electrical Charge|charge]] and [[mass]] of an [[Alpha Particle|α-particle]] by sending it between two [[Electrical Charge|electrically charged]] plates and observing its path. The '''α-particle''' moves towards the [[Negative Charge|negative]] plate, so it must be [[Positive Charge|positively charged]]. The rate of curvature depends on the [[mass]]:[[Electrical Charge|charge]] [[ratio]] which indicates it has a [[Relative Atomic Mass|relative atomic mass]] of 4 and [[Relative Atomic Charge|relative charge]] of +2.|} ====Penetration Depth===={| class="wikitable"|-|[[File:AlphaPenetrationAir.png|center|200px]]| style="height:20px; width:400px; text-align:left;" |[[Alpha Particle|Alpha particles]] can travel around 15cm through [[air]] ([[STP]]) before [[colliding]] with and [[ionising]] [[atom]]s or [[molecule]]s.|} {| class="wikitable"|-|[[File:AlphaPenetration.png|center|200px]]| style="height:20px; width:400px; text-align:left;" |[[Alpha Particle|Alpha particles]] can be stopped by a thin sheet of paper.|} ====Ionising Potential====: With a [[Electrical Charge|charge]] of +2, '''α-particles''' are the most [[Ionising Radiation|ionising]] of the three [[Ionising Radiation|ionising radiations]]. It is capable of removing two [[electron]]s from a single [[atom]] or [[molecule]] or removing 1 [[electron]] from two [[atom]]s or [[molecule]]s.{| class="wikitable"|-|[[File:AlphaIonise.png|center|600px]]|-| style="height:20px; width:600px; text-align:left;" |When an [[Alpha Particle|α-particle]] interacts with an [[atom]] the [[Alpha Particle|α-particle]] can remove one or two [[electron]]s to '''ionise''' the [[atom]].|} ===Precautions===: [[Alpha Particle|Alpha radiation]] is the most [[Ionising Radiation|ionising]] but the least [[Penetration Depth|penetrating]].: [[Alpha Particle|Alpha]] sources are kept inside a block of [[lead]] with a hole that only allows the [[Alpha Particle|alpha particles]] out in one direction.: Outside the body an [[organism]] can be protected from [[Alpha Particle|alpha radiation]] by keeping a distance greater than 5cm or by covering any bare skin.: Inside an [[organism]] [[Alpha Particle|alpha particle]]s are the most dangerous as they are highly [[Ionising Radiation|ionising]] and there is nothing inside an [[organism]] to block them [[Ionising Radiation|ionising]] biological [[molecule]]s like [[DNA]]. Every precaution must be taken not to [[Radioactive Contamination|contaminate]] the skin with the [[Alpha Particle|alpha]] source in case it finds its way into the body through a cut or the mouth.: When handling a source of [[Alpha Particle|alpha radiation]] the precautions which should be taken are::*Wear gloves - to prevent [[Radioactive Contamination|contamination]].:*Use tongs more than 5cm long to handle the source, never touch it - to prevent [[Radioactive Contamination|contamination]] and [[irradiation]].:*Aim the source away from any living [[organism]] - to prevent [[irradiation]].:*Store the source in a sealed container - to prevent [[Radioactive Contamination|contamination]] and [[irradiation]]. ===Applications==={| class="wikitable"|-|[[File:SmokeDetector.png|center|600px]]|-| style="height:20px; width:600px; text-align:left;" |In a smoke detector [[Alpha Particle|alpha particles]] are released between two [[electrode]]s. When the [[Alpha Particle|alpha particles]] [[Ionising Radiation|ionise]] the [[molecule]]s in the [[air]] the [[ion]]s move between the [[electrode]]s and a [[Electrical Current|current]] flows in the [[circuit]]. When smoke gets between the [[electrode]]s the [[ion]]s become stuck in large [[particle]]s of [[soot]] preventing them from moving. This stops the [[Electrical Current|current]] in the [[circuit]]. The [[ammeter]] in the [[circuit]] is connected to an alarm which goes off when there is no [[Electrical Current|current]].|} ===Equation===<math>_Z^AX \rightarrow _{Z-2}^{A-4}Y + _2^4\alpha</math> <math>_{92}^{238}U \rightarrow {}_{90}^{234}Th + {}_2^4\alpha</math>