F.3 chem about bonding ?????

1. why helium has weak van der waal's force?

Ans: Because helium has a simple molecular structure...(depend on the no of mark of the qn , if 1 marks just say it has simple molecular structure)

2. Except simple molecular structure 的 substabces,仲有什麼是有

weak van der waal's force?

Ans : graphite

3.咁係唔係所有 noble gases 都有 weak van der waal's force?

Ans : yup, All gases are simple molecules... so they have van der waal's forces...

4.helium is insert ,but why can still join with other elements?


Ans: Assuming He is present in other compounds... den could b bcos of induced dipole attractions...

2008-05-25 13:08:31 補充：
van der walls force is basically the intermolecular force the molecules have for one another

2008-05-25 13:12:37 補充：
for simple molecular molecules, it's not the covalent, but van de waals.....which is divided into permanet dipole dipole , induced dipole dipole, and hydrogen bonding

2008-05-25 13:12:50 補充：
For giant covalent, it is the covalent force

首先
1)所有分子與分子之間都有weak van der waal's force.
Helium原子自己本身都係氣體。所以佢本身都係molecule。

2)係「SIMPLE」 molecular structure 先有 「WEAK」 van der waal's force。van der waal's force會隋分子質量增加。

所以，較more complex既分子就會有較強既van der waal's force。
就因為咁,

咁係唔係所有 noble gases 都有 weak van der waal's force?

係要睇佢既質量(mass).

helium is insert ,but why can still join with other elements?
中四中五都冇講過。可能高級和度先會讀。暫時死計住佢有既compound先。