Chemistry......MC ...要解釋

Question

In which of the following substances are the molecules closest apart from each other at room temperature and pressure ?

A. mercury
B. diamond
C.bromine
D.Chlorine

Answer 1

The answer is : C. bromine
A is not the answer. Mercury has giant metallic structure, and the constituent particles are mercury atoms, not molecules.
B is not the answer. Diamond has giant covalent structure, and the consituent particles are carbon atoms, but not molecules.
Both bromine and chlorine have simple molecular structure, and constituent particles are bromine and chlorine molecules respectively. Bromine molecules are held closer apart than chlorine molecules at room temperature and pressure, because bromine is a volatile liquid while chlorine is a gas.

Answer 2

The answer is B. diamond.

It is because C and D (bromine and chlorine) are at gaseous states in room condition. So their molecules can move freely to any space and they are the most apart from each other.

A. mercury is liquid at room condition. The molecules are more closer than in gaseous but still they can vibrate freely.

In a solid, molecules are closest each other. They can only vibrate in their own position. That's why the shape of a solid cannot be changed so easily.