唔明個答案..(melting point)

你個網址刪除左 不過我大概明白你講咩

首先, 你會知道 當non-metal同non-metal form 一個bonding
就會有"2"個structure
分別係giant covalent structure 同埋simple molecular structure
2樣有咩唔同? 睇住
giant covalent structure have a strong covalent bond between atoms
simple molecular structure have a weak van der Waals forces between molecules
咁weak van der Waals force就係intermolecular force
你要記住 o係simple molecular structure 每一粒molecule都係好勁
但係因為中間有個weak van der Waals force o係度 令到佢melting point好低

咁點先可以分別到covalent 同埋simple molecular 呢
有個好好既方法 就係除左[diamond, graphite]2個都係carbon黎
同埋quartz (silicon dioxide) 其他9成99都係simple molecular structure
以考會考既程度 知道e 3樣野係covalent bond就好足夠喇

intermolecular forces就係molecules之間嘅力，而covalent bond係一粒molecule入面，原子之間嘅力。
如果係物理上嘅轉變，譬如固體變液體，咁就係睇IMF，但係如果係化學上嘅轉變，例如要將HCl變成氫氣同氯氣，咁就要睇covalent bond，因為將HCl變成氫同氯係會break咗個covalent bond。

Melting means to break down the attraction between molecules (but not to break down the single molecule into atoms or ions), therefore only the inter-molecular force is concerned in this case.

However, if the atoms are only held together by covalent bond (such as the carbon atoms in a diamond structure) without any inter-molecular attractions, melting requires breaking such string covalent bonds and hence diamond has a very high melting bond.

Get it ?