CAIE A Level Chemistry 9701 · Chemical bonding
The ammonium ion, , contains both covalent and coordinate (dative covalent) bonds.
Explain how dot-and-cross diagrams can be used to represent the bonding in . In your answer, describe the electron arrangements and the formation of the coordinate bond.
4 marks, so the mark scheme is looking for about 4 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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