本题目来源于试卷: Classification of Matter A.1 Periodic Table Elements Classification，类别为 IB化学
[单选题]
Which of the following statements regarding the melting points of2d)truhe x.3x elements are m1- 2o,vna t8dvidp1jcorr8vp1ni2-o ad, v1j mtdect?
I. Group 17 melting points increase down the group due to increased covalent bond strength
II. Lithium has a higher melting point than potassium
III. Bromine has a higher melting point than chlorine
A. $I$, $II$, and $III$
B. $I$ and $II$ only
C. $II$ and $III$ only
D. $II$ only
参考答案: C
本题详细解析:
Explanation: Group 17 melting points increase down the group due to increased strength in intermolecular forces. The molecular structures of each element are held together by London (dispersion) forces. These increase with the number of electrons in the molecule. Therefore statement I is not true, but III is.
Group 1 melting points decrease down a group due to decreasing metallic bond strength (with increase of atomic radius), therefore statement II is also true.
| 
