Diamond is the hardest substance known while graphite is one of the softest. both are made only of carbon atoms. what is the most likely reason why this is true? a. both are bonded ionically. b. both are bonded covalently. c. the carbon atoms are arranged differently in diamond than in graphite. d. the carbon atoms in diamond are bonded to each other but in graphite there are no bonds.

The correct answer is C. The carbon atoms are arranged differently in diamond than in graphite.

Explanation:

Diamond and graphite are solid and different structures despite being formed by carbon atoms.

In the case of graphite, the C atoms exhibit sp² hybridization. This means that each carbon atom is linked to another 3 by a covalent bond,  forming laminar structures (that is, sheets of carbon atoms are formed.).

In the diamond, the C atoms exhibit a sp³ hybridization, each one joining 4 other C atoms through a covalent bond and forming a three-dimensional structure.

This difference in structures explains that graphite is one of the softest materials, because the links between the sheets are very weak and it is easily exfoliable while diamond is the hardest substance known due to precisely that three-dimensional structure of covalent bonds.

Finally, the correct answer is C. The carbon atoms are arranged differently in diamond than in graphite.

the answer for sodium is 0.186

the answer for rubidium is 0.251