Ionic Bonding and Ionic Compounds Section 6-3

Terms:  Ionic Compound: composed of positive and negative ions combined as to be neutral.  Formula Unit: the simplest collection of atoms from which an ionic compound’s formula can be established.

Ionic Compound Formation  As atoms with high electronegativity differences approach each other, electrons may be transferred as to form ions.

Crystal Lattice  An orderly arrangement of ions that minimizes PE.  Shape influenced by size and type of ions  Lattice energy is the energy released when the crystal forms.

Ionic vs. Molecular Compounds  Ionic compounds tend to:  Have higher melting and boiling points  Be harder and more brittle  Be poor conductors as solids, conductors as liquids and conductors in solution.

Salt dissolving in Water See it happen!

Solution Terminology  Solute – what gets dissolved  Solvent – what does the dissolving  Soluble – able to be dissolved  Insoluble – not able to t be dissolved  Solubility – the ability of a material to be dissolved in a certain solvent  Miscibility – the ability of materials to mix

Solubility vs. Miscibility  Being soluble implies the solute disassociating into ions in solution. Solubility is measurable, so there are degrees of solubility.  Being miscible means that the materials will mix, in any proportion, to form a homogeneous mixture. Substances are either miscible or not.

“Like Dissolves Like”  The general rule of solubility. Substances that are alike in their polarity are generally soluble/miscible.  Example – the dual nature of soap.