20
2 Summary Tables
2.5 Mass Spectrometry
2.5.1 Average Masses of Naturally Occurring Elements with Masses
and Representative Relative Abundances of Isotopes [1–3]
Element
Isotope
Mass
Abundance
Element
Isotope
Mass
Abundance
H
1.00794 a,b
(in water) F
18.998403
1 H
1.007825 100 c
19 F
18.998403 100
2 H
2.014102
0.0115
Ne
20.1797 a
(in air)
He
4.002602 a
(in air)
20 Ne
19.992440 100 c
3 He
3.016029
0.000134
21 Ne
20.993847
0.38
4 He
4.002603 100
22 Ne
21.991385
10.22
Li
6.941 a
Na
22.989769
6 Li
6.015123
8.21 d
23 Na
22.989769 100
7 Li
7.016005 100
Mg
24.3050
Be
9.012182
24 Mg
23.985042 100
9 Be
9.012182 100
25 Mg
24.985837
12.66
26 Mg
25.982593
13.94
B
10.811 a
10 B
10.012937
24.8 c
Al
26.981538
11 B
11.009305 100
27 Al
26.981538 100
C
12.0107 a
Si
28.0855 a
12 C
12.000000 100
28 Si
27.976927 100
13 C
13.003355
1.08
29 Si
28.976495
5.080
30 Si
29.973770
3.353
N
14.0067 a
14 N
14.003074 100
P
30.973762
15 N
15.000109
0.365
31 P
30.973762 100
O
15.9994 a
S
32.065 a
16 O
15.994915 100
32 S
31.972071 100 c
17 O
16.999132
0.038
33 S
32.971459
0.79
18 O
17.999161
0.205
34 S
33.967867
4.47
36 S
35.967081
0.01