①HCl ②H2O ③N2 ④H2O2 ⑤C2H4 ⑥C2H2
化学键
H-H
H-Cl
H-Br
Cl-Cl
Br-Br
键能/(kJ•mol-1)
436.0
431.8
366.0
242.7
193.7