Option 1 states that diamond has a tetrahedral structure, while graphite has a hexagonal planar structure. This statement is correct. Diamond and graphite are both forms of carbon, but they have different crystal structures. Diamond`s tetrahedral structure gives it a very strong and rigid lattice, which contributes to its hardness. Graphite`s hexagonal planar structure allows for the layers of carbon atoms to slide over each other, which gives graphite its lubricating properties.

Option 2 states that both the physical and chemical properties of diamond and graphite are different. This statement is correct. While diamond and graphite are made up of carbon atoms, their different structures result in distinct physical and chemical properties. Diamond is a hard and transparent material, while graphite is soft and opaque. Diamond is an excellent thermal conductor, whereas graphite is a good electrical conductor. These differences are a result of the variation in their crystal structures.

Option 3 states that graphite is soft, but diamond is hard. This statement is correct. Diamond is one of the hardest known materials, scoring a 10 on the Mohs scale of hardness. In contrast, graphite is a soft material that can easily leave marks and be used as a lubricant.

Option 4 states that graphite is a good conductor of electricity,