Dot & Cross Diagrams
Chemistry: Edexcel IGCSE, topic 6.1.1
Dot-and-Cross Diagrams
Dot-and-cross diagrams can show electrons being transferred and ions being formed. Dots represent electrons from 1 atom and crosses represent electrons from the other atom. Square brackets and a charge (e.g. 2+) represent ions.
Sodium + Fluorine
- The sodium atom transfers its outer electron to the fluorine atom, creating Na+ and F- ions. Both of these ions have full outer shells.
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Calcium + Oxygen
- The calcium atom transfers its 2 outer electrons to the oxygen atom, creating Ca2+ and O2- ions which both have full outer shells.
Test yourself on Dot & Cross Diagrams
What can we show using dot-and-cross diagrams?
Sodium is in group 1 and oxygen is in group 6. In the dot-and-cross diagram for sodium oxide, how many sodium ions would there be?