Unified Atomic Mass Units - Revision history

NRJC: /* About Unified Atomic Mass Units */

2024-05-22T10:54:52Z

‎About Unified Atomic Mass Units

NRJC at 19:30, 19 May 2024

2024-05-19T19:30:31Z

NRJC: 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..."

2019-07-19T15:56:54Z

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..."

New page

==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>
|}

@@ Line 5: / Line 5: @@
 ===About Unified Atomic Mass Units===
 *Used to express atomic and [[Molecule|molecular]] masses.
-*1 u = 1.660539040 x 10^-27 kg.
+*1 u = 1.660539040 x 10<sup>-27</sup> [[Kilogram|kg]].
 *Provides a convenient scale for comparing the masses of atoms.
 *'''Unified atomic mass units''' may be denoted with a lower case 'u' or with an upper case 'D', followed by a lower case 'a'.

@@ Line 4: / Line 4: @@
 ===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'.
+*Used to express atomic and [[Molecule|molecular]] masses.
-: 1 '''unified atomic mass unit''' is approximately equal to the [[mass]] of a free [[nucleon]] ([[proton]] or [[neutron]]).
+*1 u = 1.660539040 x 10^-27 kg.
-: 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]].
+*Provides a convenient scale for comparing the masses of atoms.
 ===Examples===