Carbon dioxide is a gas at room temperature while silicon dioxide is a solid at room temperature with a melting point of 1770°C. Explain this by comparing their particles and those forces between these particles.

Although C and Si are both group 4 elements, C is much smaller than Si and can form double bonds with two oxygen atoms whereas Si is larger and so forms single bonds with four oxygen atoms. This means that carbon dioxide is composed of individual molecules (CO₂) whereas silicon dioxide is simply an extended network of giant covalent structure with an empirical formula of SiO₂. The covalent bonds between the atoms within the individual CO₂ molecules are strong but the intermolecular forces (idid) are weak. The energy required to break those weak intermolecular forces (idid) between each CO₂ molecule is much lower than the energy required to break the strong individual Si-O covalent bonds (melting the silicon dioxide). Therefore carbon dioxide has a much lower melting point and boiling point than silicon dioxide.