R EVIEW Electronegativity is the ability to attract electrons.

R EVIEW Polar molecules: Bonds between two atoms with different electronegativities.

R EVIEW Non Polar molecules: Bonds between two atoms with similar electronegativities.

Q UESTION Which of the following will be polar molecules? Include a diagram and justify your answer. HCl F 2 I 2 CH 3 Cl

T HE S OLUTION P ROCESS OF S IMPLE I ONIC AND C OVALENT C OMPOUNDS

R EVIEW Ionic bond - transfer of electrons between a metal (cation) and non-metal (anion) Covalent bond- sharing of electrons between two non-metals (anions) Covalent bonds can be polar or non-polar.

I ONIC C OMPOUNDS When a solute is placed into a solvent, the solvent particles completely surround the surface of the solute particles. The polar water molecules orientate themselves around each exposed ion on the surface of the solid.

I ONIC C OMPOUNDS

If the solute is soluble, the attraction between the solvent solute increases to the point where it finally exceeds the forces holding the crystal lattice. The separation of an ionic compound into ions is called dissociation

I ONIC C OMPOUNDS Solvation is the process of the solvent surrounding the solute ions.

I ONIC C OMPOUNDS If the solvent is water than the process of solvation can be called hydration and the solute particles are hydrated.

I ONIC C OMPOUNDS ogy1111/animations/dissolve.html

I ONIC C OMPOUNDS Dissociation: NaCl (s) → Na + (aq) + Cl - (aq) KF (s) → K + (aq) + F - (aq) NH 4 NO 3(s) →

C OVALENT C OMPOUNDS An entire molecule is pulled away from the solid structure and is surrounded by the solvent. C 12 H 22 O 11(s)  C 12 H 22 O 11(aq)

Q UESTIONS 1. Explain the process of CaCl 2 dissolving in water. Include a diagram in your explanation. 2. Compare and contrast dissolving ionic compounds and covalent compounds. 3. Use your knowledge of dissociation and solvation to explain why stirring powdered hot chocolate and water dissolves the crystals faster.