Editing Spin quantum number (section)

==Nuclear spin==
[[Atomic nucleus|Atomic nuclei]] also have spins. The nuclear spin {{mvar|I}} is a fixed property of each nucleus and may be either an integer or a half-integer. The component {{mvar|m}}<sub>{{mvar|I}}</sub> of nuclear spin parallel to the {{mvar|z}}-axis can have (2{{mvar|I}} + 1) values {{mvar|I}}, {{mvar|I}}−1, ..., −{{mvar|I}}. For example, a [[isotopes of nitrogen|{{sup|14}}N]] nucleus has {{mvar|I}} = 1, so that there are 3 possible orientations relative to the {{mvar|z}}-axis, corresponding to states {{mvar|m}}<sub>{{mvar|I}}</sub> = +1, 0 and −1.<ref>{{cite book |last1=Atkins |first1=Peter |last2=de&nbsp;Paula |first2=Julio |year=2006 |title=Atkins' Physical Chemistry |edition=8th |publisher=W.H. Freeman |isbn=0-7167-8759-8 |page=515}}</ref>

The spins {{mvar|I}} of different nuclei are interpreted using the [[Nuclear shell model#Other properties of nuclei|nuclear shell model]]. [[Even and odd atomic nuclei|Even-even nuclei]] with even numbers of both protons and neutrons, such as [[isotopes of carbon|{{sup|12}}C]] and [[isotopes of oxygen|{{sup|16}}O]], have spin zero. Odd mass number nuclei have half-integer spins, such as {{sfrac|3| 2 }} for [[isotopes of lithium|{{sup|7}}Li]], {{sfrac| 1 |2}} for [[isotopes of carbon|{{sup|13}}C]] and {{sfrac|5| 2 }} for [[isotopes of oxygen|{{sup|17}}O]], usually corresponding to the angular momentum of the last [[nucleon]] added. Odd-odd nuclei with odd numbers of both protons and neutrons have integer spins, such as 3 for [[isotopes of boron|{{sup|10}}B]], and 1 for [[isotopes of nitrogen|{{sup|14}}N]].<ref>{{cite book |last1=Cottingham |first1=W.N. |last2=Greenwood |first2=D.A. |year=1986 |title=An introduction to nuclear physics |publisher=Cambridge University Press |isbn=0-521-31960-9 |pages=36, 57}}</ref> Values of nuclear spin for a given isotope are found in the lists of isotopes for each element. (See [[isotopes of oxygen]], [[isotopes of aluminium]], etc. etc.)