想極都唔明的chem question

oxygen gas consists of discrete molecules at room conditions即係
氧氣係氣態中既分子係獨立既......氧氣係由好多個氧分子(O2)組成...而分子molecule就係一舊由多個(可相同)non-metal atom組成既而又stable既野.......o2係room condition係好stable.....
as a result, oxygen gas consists of discrete(獨立, 分開) molecules at room conditions

sulphur dioxide (SO2).......好stable既一舊野............面又係non-metal組成(S, O)
bromine (Br2).......... 好stable既一舊野............面又係non-metal組成(Br)
as a result, sulphur dioxide,bromine 係ｍolecule

請問樓上的勁人
既然sulphur dioxide (SO2)好stable, 為何又被用作防腐劑,它那麼stable為何又會參與還原反應?
non-metal組成又跟molecule有何關係?
君不見non-metal可以有giant covalent structure而偏偏metal亦可以有molecule?(如Mg,organometallic molecules)

嚴格來說只能以octet rules部份地來解釋為何bromine等元素以molecules形態出現
至於為何sulphur dioxide等以molecules出現而不是giant covalent structure出現, 則牽涉到究竟哪一種形態比較choas, 亦牽涉到複雜的計算, 不是那麼容納解釋(例如為何CO2是molecules但SiO2是giant covalent structure等問題)
樓上的勁人, 你有機會上到大學的話便會有機會學到了

2007-11-17 00:17:33 補充：
是Chaos不是choas