Based on their structures, explain why sodium oxide, silicon dioxide and carbon dioxide have different melting points.

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Add any comments and corrections to each answer. Then put them into a 2-3-1 diamond ranking.

Ambaka

Sodium dioxide, silicon dioxide and carbon dioxide have giant ionic structure, giant covalent structure and molecular structure respectively. As the ionic bonds (attractive force) between the ionic are very strong. Therefore more energy (heat) is required to break the structure. Thus, the melting point of ions is very high. The covalent bonds between the atoms are very strong too. Therefore, more energy (heat) is also required to break down the structure. The melting point is very high. The Van der Waal’s force between the molecules is weak. Therefore, less energy (heat) is required to break the structure slowly. Thus, the melting point of the molecular structure (carbon dioxide) is low.

As 3 of them have different structures, the strength of their attractive forces are different. And different strength of attractive forces cause different melting points. For silicon dioxide, it has giant covalent structure. It’s attractive bonds are covalent bonds, and covalent bonds are strong force. For sodium oxide, it has giant ionic structure, it’s attractive bonds are ionic bonds, and they’re also strong force but not the same as that of covalent bonds. For carbon dioxide, it has, it’s attractive force is Van D W’s force, it’s a very weak force. As higher melting point is needed to melt stronger force, difference strength of force cause different melting point.

Ben

For sodium oxide, it’s an ionic compound. The ionic bonds between the ions are strong. Therefore, large amount of energy is required to break down the structure of sodium oxide as it has a giant ionic structure. For silicon dioxide, it’s a covalent compound. The covalent bonds between the atoms are very strong. As the result, a very strong energy is required to break down the silicon dioxide because it has a giant covalent structure. For carbon dioxide, it just has a simple molecular structure. The Van der Waals’ force between the molecules is weak so that a less energy is required to break it down.Therefore, sodium oxide and silicon dioxide both have a higher melting point. But carbon dioxide doesn’t.

Catia

DeshalSodium and oxygen combine to form sodium oxide by ionic bonds. Two sodium ions lose one electrons in order to become stable as well as an oxide ion receives two electrons to become stable. Then, it has a giant ionic structure that large amount of energy is required to break it down, so it has a high melting point. Silicon and oxygen combine to form silicon dioxide by covalent bonds. Silicon and oxide both share their electrons to become stable. Then, a giant covalent structure is obtained that the giant covalent structure require a large amount of energy to break it down. So silicon dioxide has a very high melting point. Carbon and dioxide combine to form carbon dioxide. But the Van der Waal’s force between the molecules is weak. Because carbon dioxide has a simple molecular structure that it can be broken down easily.

ErikaThe three compounds have different melting points because they have different structures. Their form of compounds are different. Some are solid and some are liquid and gases. Solid have a higher melting point compare with liquid and gases as the attractive forces between them are stronger. For the solid elements, some are metals and some are non-metal. Metals have a higher melting compare with non-metals as its ionic bonding is stronger. This lead the difference of melting point on different compound.

FaisalSodium oxide is a giant ionic structure. It has a very high melting point as the ionic bond is very strong between them. More force is required to break down. Silicon dioxide is a giant covalent structure. It also has the highest melting point because the covalent bonds between them is the strongest. Carbon dioxide is a simple molecular structure. It has a lower melting point since the van der Waals’ force between them is not as strong as ionic bond and covalent bond.