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Created page with "==Key Stage 5== ===Meaning=== '''Unified atomic mass units''' ('''u''' or '''Da''') is an SI unit equivalent to the mass of 1/12th the mass of a Carbon..."
==Key Stage 5==
===Meaning===
'''Unified atomic mass units''' ('''u''' or '''Da''') is an [[SI Unit|SI unit]] equivalent to the [[mass]] of 1/12th the [[mass]] of a [[Carbon]] [[atom]].
===About Unified Atomic Mass Units===
: '''Unified atomic mass units''' may be denoted with a lower case 'u' or with an upper case 'D', followed by a lower case 'a'.
: 1 '''unified atomic mass unit''' is approximately equal to the [[mass]] of a free [[nucleon]] ([[proton]] or [[neutron]]).
: A free [[nucleon]] has a [[mass]] slightly greater than 1'''u''', but when a [[nucleon]] is bound within a [[nucleus]] some of the [[mass]] of the free [[nucleon]] has been converted into [[energy]] due to the [[Mass-Energy Equivalence|mass energy equivalence]], giving it a slightly smaller [[mass]].
===Examples===
{| border="1" style="border-collapse:collapse"
| style="height:20px; width:150px; text-align:center;"|[[Subatomic Particle|Particle]]
| style="height:20px; width:150px; text-align:center;"|[[Rest Mass]] / kg
| style="height:20px; width:150px; text-align:center;"|'''Unified Atomic Mass Units'''
| style="height:20px; width:150px; text-align:center;"|[[Rest Energy]] / MeV
|-
| style="height:20px; width:150px; text-align:center;"|[[Proton]] (<math>p</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.007</math>
| style="height:20px; width:150px; text-align:center;"|<math>938</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Neutron]] (<math>n</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.009</math>
| style="height:20px; width:150px; text-align:center;"|<math>939</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Electron]] (<math>e</math>)
| style="height:20px; width:150px; text-align:center;"|<math>9.11\times10^{-31}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.05486</math>
| style="height:20px; width:150px; text-align:center;"|<math>5.11</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Muon]] (<math>\mu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.88\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1134</math>
| style="height:20px; width:150px; text-align:center;"|<math>106</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[π-meson]] (<math>\pi^±</math>)
| style="height:20px; width:150px; text-align:center;"|<math>2.49\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1500</math>
| style="height:20px; width:150px; text-align:center;"|<math>140</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[π-meson]] (<math>\pi^0</math>)
| style="height:20px; width:150px; text-align:center;"|<math>2.41\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1449</math>
| style="height:20px; width:150px; text-align:center;"|<math>135</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[K-meson]] (<math>K^±</math>)
| style="height:20px; width:150px; text-align:center;"|<math>8.80\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5300</math>
| style="height:20px; width:150px; text-align:center;"|<math>494</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[K-meson]] (<math>K^0</math>)
| style="height:20px; width:150px; text-align:center;"|<math>8.87\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5442</math>
| style="height:20px; width:150px; text-align:center;"|<math>498</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Photon]] (<math>\gamma</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Neutrino]] (<math>\nu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|}
===Meaning===
'''Unified atomic mass units''' ('''u''' or '''Da''') is an [[SI Unit|SI unit]] equivalent to the [[mass]] of 1/12th the [[mass]] of a [[Carbon]] [[atom]].
===About Unified Atomic Mass Units===
: '''Unified atomic mass units''' may be denoted with a lower case 'u' or with an upper case 'D', followed by a lower case 'a'.
: 1 '''unified atomic mass unit''' is approximately equal to the [[mass]] of a free [[nucleon]] ([[proton]] or [[neutron]]).
: A free [[nucleon]] has a [[mass]] slightly greater than 1'''u''', but when a [[nucleon]] is bound within a [[nucleus]] some of the [[mass]] of the free [[nucleon]] has been converted into [[energy]] due to the [[Mass-Energy Equivalence|mass energy equivalence]], giving it a slightly smaller [[mass]].
===Examples===
{| border="1" style="border-collapse:collapse"
| style="height:20px; width:150px; text-align:center;"|[[Subatomic Particle|Particle]]
| style="height:20px; width:150px; text-align:center;"|[[Rest Mass]] / kg
| style="height:20px; width:150px; text-align:center;"|'''Unified Atomic Mass Units'''
| style="height:20px; width:150px; text-align:center;"|[[Rest Energy]] / MeV
|-
| style="height:20px; width:150px; text-align:center;"|[[Proton]] (<math>p</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.007</math>
| style="height:20px; width:150px; text-align:center;"|<math>938</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Neutron]] (<math>n</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.67\times10^{-27}</math>
| style="height:20px; width:150px; text-align:center;"|<math>1.009</math>
| style="height:20px; width:150px; text-align:center;"|<math>939</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Electron]] (<math>e</math>)
| style="height:20px; width:150px; text-align:center;"|<math>9.11\times10^{-31}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.05486</math>
| style="height:20px; width:150px; text-align:center;"|<math>5.11</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Muon]] (<math>\mu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>1.88\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1134</math>
| style="height:20px; width:150px; text-align:center;"|<math>106</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[π-meson]] (<math>\pi^±</math>)
| style="height:20px; width:150px; text-align:center;"|<math>2.49\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1500</math>
| style="height:20px; width:150px; text-align:center;"|<math>140</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[π-meson]] (<math>\pi^0</math>)
| style="height:20px; width:150px; text-align:center;"|<math>2.41\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.1449</math>
| style="height:20px; width:150px; text-align:center;"|<math>135</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[K-meson]] (<math>K^±</math>)
| style="height:20px; width:150px; text-align:center;"|<math>8.80\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5300</math>
| style="height:20px; width:150px; text-align:center;"|<math>494</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[K-meson]] (<math>K^0</math>)
| style="height:20px; width:150px; text-align:center;"|<math>8.87\times10^{-28}</math>
| style="height:20px; width:150px; text-align:center;"|<math>0.5442</math>
| style="height:20px; width:150px; text-align:center;"|<math>498</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Photon]] (<math>\gamma</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|-
| style="height:20px; width:150px; text-align:center;"|[[Neutrino]] (<math>\nu</math>)
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
| style="height:20px; width:150px; text-align:center;"|<math>0</math>
|}