Describe the bonding and structure of silicon dioxide (SiO2).

Silicon dioxide (SiO2) has a giant covalent structure where each silicon atom is covalently bonded to four oxygen atoms in a tetrahedral arrangement. This extensive network of covalent bonds results in a very hard material with a high melting point. This answer is anchored to Period 3 oxides (A-level only).

Silicon dioxide (SiO2) has a giant covalent structure where each silicon atom is covalently bonded to four oxygen atoms in a tetrahedral arrangement. This extensive network of covalent bonds results in a very hard material with a high melting point. is the best answer because it directly supports the AQA A-Level Chemistry objective to describe the bonding and structure of Period 3 oxides. This reasoning is anchored to Period 3 oxides (A-level only) in Properties of Period 3 elements and their oxides (A-level only), and it separates Period 3 oxide from similar A-Level ideas rather than relying on a vague recall statement. Other options are weaker if they use the wrong evidence, calculation, mechanism, observation, unit, or conclusion for this subtopic.