Answer:
Diamond
Explanation:
Diamond has covalent bonds, which makes it a non-metal.
However, it also has a tetrahedral structure, which holds its C atoms together by strong forces, thus making it hard.
Diamond also has free-moving electrons due to its tetrahedral structure, thus making it possible to conduct electricity.
The third one is correct, not sure abt another one
D because Carbon and Oxygen form covalent compounds. I wasn't the greatest at chem., but I'm pretty sure this is correct :D let me know if I gave you the right answer.
The atomic mass on the periodic table represents the sum of number of protons and number of neutrons.
Atomic mass = Number of protons + number of neutrons
Hope this helps!
