1. Ionic bonding and compounds
An ionic compound is composed of positive and negative ions that are combined so that the numbers of positive charges and negative charges are equal.

2. Ionic bonding and compounds
Na and Cl combine to form
NaCl, sodium chloride
Na+ Cl-
One positive charge Na+
combines with one negative charge, Cl-

3. Ionic bonding and compounds
CaI2 , Calcium Iodide
Ca combines with I
Ca I-
To balance the pos and neg charges, the compound combines 1 Ca with 2 I
Ca2+ I- I-
Now the charges balance

4. Ionic bonding and compounds
The simplest form of a molecular compound is a molecule, but ionic compounds ARE NOT molecular compounds so we call the simplest unit of an ionic compound a
formula unit

5. Ionic bonding and compounds
A formula unit is the simplest collection of atoms of an ionic compound
Ionic compound – formula unit
Molecular compound - molecule

6. Ionic compounds form in what are called crystal lattices
A crystal lattice is an orderly arrangement of ions to minimize the ions potential energy

8. Ionic crystal lattices are hard but brittle, can break easily
All it takes to break an ionic compound is to shift the ions, one ion over to break the ionic bonds and the ionic compound breaks apart

10. The force that holds ions together, the positive and negative attraction, is very strong
The forces of attraction between atoms in molecular compounds are weaker than the forces of attraction between ions in an ionic compound.

11. Bond strength in ionic compounds is measured by the lattice energy
Lattice energy – is the energy released when one mole of an ionic crystalline compound is formed from gaseous ions.

12. Lattice energies kj/mol
NaCl
CaF
LiF
Negative energy values mean the energy is released when the solid crystals are formed

13. What is the relationship between lattice energies and bond strength?
NaCl kj/mol
CaF kj/mol

14. Polyatomic ions
A charged group of covalently bonded atoms is called a polyatomic ion

16. Ionic compounds solid v aquaeous
Solid ionic compounds cannot carry an electrical charge.
Ionic compounds dissolved in water will conduct electricity

17. Metallic bonding

18. Metallic bonds
Consist of the attraction of free-floating valence electrons with the positively charged metal ions.
so, it’s a positive and negative attractive force that holds the bonds together

19. Metal atoms arranged in very compact and orderly patterns

20. sea of electrons

21. The arrangement of atoms in a metal allows the metal to bend or change shape without breaking or shattering. (malleable)
Ionic crystal bonding is different from metallic bonding.

22. Metallic vs Ionic Metallic bond ionic bond
Atoms can flow atoms are not able to
Around each other flow, will shatter if shifted

23. alloys Alloys are made up of two or more metal elements.
Bronze is an alloy of copper and tin. Used early in history to make weapons (bronze age)
Stainless steel is also an alloy of Fe 80.6%,
Cr 18%, C .4%, Ni 1%
Alloys are important, their properties are often superior to those of the individual elements.

24. Diatomic Molecules
There are 7 diatomic molecules, or elements that cannot exist as a single atom, but two atoms of the same element bonded together.
N2, O2, H2, F2, Cl2, Br2, I2