Nitrogen-21

Properties and data of the isotope ²¹N.

Content

General data

Name of the isotope:Nitrogen-21; N-21Symbol:²¹N or 217NMass number A:21 (= number of nucleons)Atomic number Z:7 (= number of protons)Neutrons N:14Isotopic mass:21.02709(14) u (atomic weight of Nitrogen-21)Nuclide mass:21.02325 u (calculated nuclear mass without electrons)Mass excess:25.23417 MeVMass defect:0.148994048 u (per nucleus)Nuclear binding energy:138.78706175 MeV (per nucleus)
6.6089077 MeV (average binding energy per nucleon)Separation energy:S_N = 4.61(16) MeV (first neutron)
S_P = 19.56(27) MeV (first proton)Half-life:84(7) msDecay constant λ:8.2517521495232 s^-1Specific activity α:2.366343513605 × 10⁺²³ Bq g^-1
6395523009744.3 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2-)Year of discovery:1970

Radioactive Decay

Half-life T_½ = 84(7) ms respectively 8.4 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²¹O	14 %	17.17(13) MeV
β^-, n	²⁰O	86(4) %	13.36(13) MeV

Parent Nuclides

Direct parent isotope is: ²²C.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 14) and isobaric (same nucleon number A = 21) with Nitrogen-21. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 14	Isobar A = 21
5	¹⁹B	²¹B
6	²⁰C	²¹C
7	²¹N	²¹N
8	²²O	²¹O
9	²³F	²¹F
10	²⁴Ne	²¹Ne
11	²⁵Na	²¹Na
12	²⁶Mg	²¹Mg
13	²⁷Al	²¹Al
14	²⁸Si
15	²⁹P
16	³⁰S
17	³¹Cl
18	³²Ar
19	³³K
20	³⁴Ca