A pencil mark and a cutting edge begin with carbon. Look at the connections before you explain the difference.
Graphite
Layered sheets
3 bonded neighbors per interior atom
Strong connections within a sheet; weaker interactions between sheets.
Diamond
Connected network
4 neighbors in the bulk
A connected, three-dimensional network rather than separate sheets.
C
What stays the same? Every carbon nucleus has 6 protons. Arrangement changes; element identity stays.
Idealized crystal fragments: cropped edge sites show fewer neighbors. Spheres and connectors are a structural explanation, not a calculation of hardness or conductivity.
Optional: check your understanding
MAKE THE CONNECTION
What explains the structural difference shown here?
