The Covalent Bond and Molecular Compounds Chemistry Mrs. Coyle

The Periodic Table and Atomic Radius

Types of Bonds Ionic Metallic Covalent

The Covalent Bond The bond in which atoms are held together by their mutual electrical attraction for shared electrons. Fluorine

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The Covalent Bond A single covalent bond is made up of two electrons. The covalent bond is represented using a straight line. F — F F

Molecule A neutral group of atoms joined together by covalent bonds.

Diatomic Molecules Molecules made up of two atoms. There are 7 diatomic molecules. H 2, N 2, O 2, F 2, Cl 2, Br 2, I 2

Hydrogen H· + ·H  H:H Hydrogen Hydrogen Hydrogen Atom Atom molecule The hydrogen molecule has a single covalent bond. The electronegativity of each hydrogenatom is the same, so the electrons are shared. Shared electron pair

Molecular Compounds Compounds comprised of molecules.

Ionic CompoundsMolecular Compounds Crystal LatticeMolecule Types of Elements Metal with non-metal or polyatomic ions Non-metal with non-metal Physical State SolidSolid, liquid or gas Melting PointHigh > 300  C Low <300  C Solubility in water Generally highGenerally low Electrical conductivity of solution Good conductorPoor to none

Molecular Formula A molecular formula is a chemical formula that is used for molecular compounds. It shows the types and number of atoms in a molecule. Note that ionic compounds used the chemical formula called the formula unit. A molecular formula does not give information about the molecules structure.

Structural Formula Structural formulas show the arrangement of atoms in a molecule. In a structural formula, the electron pair is represented by a line Example: H-H (single bond: one pair of electrons)

Space Filling Model Methane CH 4

Ball and Stick Models Ethane C 2 H 6

The Water Molecule

The Ammonia Molecule. NH 3