Dot & Cross Diagrams (AQA AS Chemistry) : Revision Note

Representing Dot & Cross Diagrams

• Dot and cross diagrams are diagrams that show the arrangement of the outer-shell electrons in an ionic or covalent compound or element

  • The electrons are shown as dots and crosses

• In a dot and cross diagram:

  • Only the outer electrons are shown

  • The charge of the ion is spread evenly which is shown by using brackets

  • The charge on each ion is written at the top right-hand corner

Ionic compounds

• Ionic bonds are formed when metal atoms transfer electrons to a non-metal to form a positively charged and negatively charged ion

• The atoms achieve a noble gas configuration

Dot-and-cross diagrams of ionic compounds in which one of the atoms transfers their valence electrons to the other

Covalent compounds

• The atoms in covalent compounds will share their outer valence electrons to achieve a noble gas configuration

Dot-and-cross diagrams of covalent compounds in which the atoms share their valence electrons