I have five questions someone please help

Question

annah.bee · Answer

Diamond and graphite are both made of carbon. However, diamond is much harder than graphite. Which of the following statements best explains the difference between diamond and graphite
  a. Diamond has a more rigid structre than graphite
 b. Graphite has a free electron present and diamond does not
 c. Diamond is a denser material than graphite.
 d. Graphite is made of a different carbon isotope than diamond.

bartyrocks3 · Answer

The answer is D.

anonymous · Answer

I disagree. Physical properties are caused by behaviors on the molecular structure. If its atomic structure is more rigid, the material will consequently be stronger and harder.

gollywolly · Answer

They are allotropes of carbon. They are just structurally different. diamond has a tetrahedral orientation and graphite is trigonal planar. Graphite is less dense due to gaps between layers.

gollywolly · Answer

The answer is a.