周期/族
IA
0
1
1 H
1.008
ⅡA
ⅢA
ⅣA
ⅤA
ⅥA
ⅦA
2 He
4.003
2
3 Li
6.941
4 Be
9.012
①
6 C
12.01
7 N
14.01
8 O
16.00
9 F
19.00
10 Ne
20.81
3
②
12 Mg
24.31
13 Al
26.98
14 Si
28.09
15 P
30.97
16 S
32.06
③
18 Ar
39.95