International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What characterizes the arrangement of atoms in graphite?

1. Layers of tightly packed atoms

2. A random arrangement of atoms

3. A giant covalent structure

4. Atoms arranged in sheets with weak forces between them

The correct answer is: Atoms arranged in sheets with weak forces between them

The correct choice highlights an essential aspect of graphite’s structure. In graphite, the arrangement of atoms forms layers or sheets, which are composed of carbon atoms that are bonded together in a planar hexagonal lattice. Within these layers, each carbon atom is covalently bonded to three other carbon atoms, creating strong bonds within the sheets. However, the unique characteristic of graphite arises from the fact that these layers are held together by weak van der Waals forces. This allows the layers to slide over one another easily, giving graphite its lubricating properties and making it useful in applications such as pencil lead and lubricants. This layered structure is a defining feature of graphite, distinguishing it from other types of carbon allotropes like diamond, where the atoms are arranged in a three-dimensional tetrahedral network, leading to very different physical and chemical properties. In summary, the arrangement of atoms in graphite, with sheets and weak interlayer forces, provides insights into its behavior and applications in various fields.