鈉（原子量：2298976928 2）共有 22 個已知同位素，質量數介於 1837 之間，其中只有 1 個是穩定的，其他都具有放射性，因此鈉屬於單一同位素元素。天然存在的鈉同位素有 3 個，分別是穩定的 23Na 和具放射性的 22Na 及 24Na，其中 23Na 佔天然鈉的絕大部分，而 22Na 和 24Na 在自然界中僅痕量存在，為宇宙射線散裂所產生。其他放射性同位素都不出現在自然界中，只有在實驗室製造出來過，且半衰期都極短，非常不穩定。 圖表 rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 7 rowspan2 rowspan2 p 999 17Ne rowspan21 rowspan2 1 18Ne styletextalignright 11 styletextalignright 8 40 ns p 18Ne 52 rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 9 rowspan2 rowspan24479 23 ms β 75 20Ne rowspan22 rowspan2 β α 25 16O styletextalignright 11 styletextalignright 10 2249 4 s β 21Ne 32 styletextalignright 11 styletextalignright 11 26027 10 y β 22Ne 3 痕量 styletextindent1em colspan3 styletextindent2em 58303 9 keV 244 6 ns 1 styletextalignright 11 styletextalignright 12 colspan3 aligncenter 32 styletextalignright 11 styletextalignright 13 β 24Mg 4 痕量 rowspan2 styletextindent1em rowspan2 colspan3 styletextindent2em 472207 9 keV rowspan22020 7 ms IT 9995 24Na rowspan21 rowspan2 β 05 24Mg styletextalignright 11 styletextalignright 14 591 6 s β 25Mg 52 styletextalignright 11 styletextalignright 15 1077 5 s β 26Mg 3 rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 16 rowspan2 rowspan2 301 6 ms β 9987 27Mg rowspan252 rowspan2 β n 13 26Mg rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 17 rowspan2 rowspan2305 4 ms β 99421 28Mg rowspan21 rowspan2 β n 579 27Mg rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 18 rowspan2 rowspan2449 12 ms β 7409 29Mg rowspan232 rowspan2 β n 2591 28Mg rowspan4 rowspan4 styletextalignright 11 rowspan4 styletextalignright 19 rowspan4 rowspan4484 17 ms β 6883 30Mg rowspan42 rowspan4 β n 300 29Mg β 2n 117 28Mg β α 26Ne rowspan4 rowspan4 styletextalignright 11 rowspan4 styletextalignright 20 rowspan4 rowspan4170 4 ms β 6205 31Mg rowspan432 rowspan4 β n 30Mg β 2n 29Mg β 3n 28Mg rowspan3 rowspan3 styletextalignright 11 rowspan3 styletextalignright 21 rowspan3 rowspan3129 7 ms β 32Mg rowspan334 rowspan3 β n 31Mg β 2n 30Mg rowspan3 rowspan3 styletextalignright 11 rowspan3 styletextalignright 22 rowspan3 rowspan382 2 ms β n 520 32Mg rowspan332 rowspan3 β 360 33Mg β 2n 120 31Mg rowspan3 rowspan3 styletextalignright 11 rowspan3 styletextalignright 23 rowspan3 rowspan355 10 ms β 2n 500 32Mg rowspan31 rowspan3 β 350 34Mg β n 150 33Mg rowspan2 rowspan2 styletextalignright 11 rowspan2 styletextalignright 24 rowspan2 rowspan215 5 ms β 999 35Mg rowspan232 rowspan2 β n 1 34Mg styletextalignright 11 styletextalignright 26 3705934 103 1 ms 15 µs 32 參考文獻 Isotope masses from Ame2003 Atomic Mass Evaluation by G Audi AH Wapstra C Thibault J Blachot and O Bersillon in Nuclear Physics A729 2003 Halflife spin and isomer data selected from these sources Editing notes on this articles talk page Audi Bersillon Blachot Wapstra The Nubase2003 evaluation of nuclear and decay properties Nuc Phys A 729 pp 3128 2003 National Nuclear Data Center Brookhaven National Laboratory Information extracted from the NuDat 21 database retrieved Sept 2005 David R Lide ed Norman E Holden in CRC Handbook of Chemistry and Physics 85th Edition online version CRC Press Boca Raton Florida 2005 Section 11 Table of the Isotopes Na Category 鈉