CIE A Level Chemistry: Understanding Dot-and-Cross Diagrams (Chapter 3.7)

Dot-and-Cross Diagrams

Visual representations of outer-shell electrons in compounds.

Outer-Shell Electrons

Electrons in the highest energy level of an atom.

Ionic Bonds

Formed by electron transfer from metal to non-metal.

Noble Gas Configuration

Stable electron arrangement similar to noble gases.

Covalent Compounds

Compounds formed by sharing outer valence electrons.

Coordinate Bonding

Bond where one atom donates both electrons.

Dative Covalent Bond

Covalent bond represented by an arrow in formulas.

Expanded Octet Rule

Atoms can have more than eight electrons in outer shell.

Incomplete Octet Rule

Atoms can have fewer than eight electrons in outer shell.

Odd Number of Electrons

Some atoms may have unpaired valence electrons.

Brackets in Diagrams

Indicate the charge of ions in ionic compounds.

Valence Electrons

Electrons involved in chemical bonding.

Displayed Formula

A structural representation of a molecule.

Electron Deficient Compounds

Compounds lacking sufficient electrons for stability.

Transfer of Electrons

Movement of electrons from one atom to another.

Sharing Electrons

Atoms mutually contribute electrons to form bonds.

Charge Representation

Charge indicated at the top right of ions.

Atom Configuration

Arrangement of electrons around an atom.

Chemical Bonding

Attraction between atoms forming compounds.

Electron Pairing

Two electrons occupying the same orbital.

Chemical Stability

Achieved through full outer electron shells.

Visual Representation

Diagrams that illustrate molecular structures.

Ionic Compounds

Compounds formed from ionic bonds between metals and non-metals.