2020 Chemsirty Mistakes

Question 1

Compare silicon dioxide, carbon dioxide and magnesium oxide

Answer 1

both) carbon dioxide and silicon dioxide are made up of atoms
• (but) magnesium oxide is made up of ions
• (both) silicon dioxide and magnesium oxide are giant structures
• (but) carbon dioxide is small molecules
• with weak intermolecular forces
• all three compounds have strong bonds
• (both) carbon dioxide and silicon dioxide are formed from two
non-metals
• (so) bonds formed are covalent
• (so) electron (pairs) are shared (between atoms)
• (but) magnesium oxide is formed from a metal and a non-metal
• (so) bonds in magnesium oxide are ionic
• (so) electrons are transferred
• from magnesium to oxygen
• two electrons are transferred
• bonds in silicon dioxide are single bonds
• (where) each silicon forms four bonds
• (and) each oxygen forms two bonds
• (but) in carbon dioxide the bonds are double bonds
• (where) carbon forms two double bonds
• (and) oxygen forms one double bond
ignore properties e.g. melting point, electrical conductivity