1. Ionic Bonding

2. Valence electrons
Valence electrons – electrons in the highest occupied energy level of an element’s atoms.
Determined by looking at the group number (skipping transition metals)
Helium is the only exception (two valence electrons)
Electron Dot Structure’s show valence electrons as dots for a better understanding of bonding.
Ex:

3. Octet Rule
In forming compounds, atoms tend to achieve the electron configuration of a noble gas. (octet is a set of eight)
Metals tend to lose their electrons to form a cation and a complete octet in the next-lowest energy level.
Non-metals tend to gain electrons, or share electrons with another non-metal, to form an anion and achieve a complete octet.

4. Octet Rule Cl gains an electron to form an anion in an ionic bond
Na loses an electron to form a cation in an ionic bond
Draw orbital diagram and write electron configuration
Cl gains an electron to form an anion in an ionic bond
Na similar to Neon’s orbital diagram, Cl similar to Argon’s orbital diagram

5. Halide ions Ions that are produced when a halogen gains an electron.
Ex: Cl-

6. Identify the Element X2+, a cation with 36 electrons
X3- , an anion with 18 electrons

7. Bonds
Ionic bonds- electrostatic forces that hold ions together in ionic compounds.
result from the transfer of electrons from one element to another.
Bonding between metals and non-metals
Covalent bonds – Result from the sharing of electrons between two atoms.
Electronegativity difference can determine the type of bond that occurs:
0-0.4 non-polar covalent
polar covalent
>2.0 ionic

8. Properties of ionic Compounds
Crystalline solids at room temperature
High melting points
Conduct an electric current when melted or dissolved in water.
All salts are ionic.

9. Metallic bonds
The valence electrons of metal atoms are free floating and can be modeled as a “sea of electrons” attracted to the positively charged metal ions.
This explains why metals are good conductors of electricity! Electrons flow freely from one end of the metal to the other. (as electrons enter one end, they leave the other)

10. Alloys
Alloys – mixtures composed of two or more elements, at least one of which is a metal.
Properties are usually superior to those of their component elements. (Ex: Sterling silver, which contains silver and copper, is harder and more durable than pure silver)

11. Chemical formulas
Formula Unit (chemical formula)– lowest whole- number ratio of ions in an ionic compound.
Na+ and Cl- have a 1:1 ratio, so the chemical formula is NaCl

12. writing formulas
Determine the lowest ratio of atoms to have an overall charge of zero.
Write the symbol for the cation first, and the anion second.
Write the subscripts of the ratio.

13. Crisscross method
Write the symbol of the cation with it’s charge above, followed by the symbol of the anion with it’s charge above.
Crisscross your charges.

14. Practice writing formulas
Potassium Iodide
Gallium Bromide
Strontium Fluoride
Aluminum Selenide
Zinc Chloride

15. Naming Binary ionic compounds
Anion has an ”Ide” ending
NaCl
MgBr2
K2S

16. Naming Binary compounds with transition metals
Transition metals can form more than one ion, so we must identify which ion is forming the bond.
This is done by adding roman numerals after the metal to represent it’s charge.
Two methods to determining cation charge:
reverse crisscross
determine the charge based on the amount that will make the cation and anion add up to zero.

17. Practice
Cr2O3
2. Fe2S3
3. CuO

18. Iron (III) Chloride Copper (I) Fluoride Cobalt (II) Bromide
Write the formula
Iron (III) Chloride
Copper (I) Fluoride
Cobalt (II) Bromide

19. Review
Write the compound name or formula for the following ionic compounds:
Copper (II) Fluoride
MgBr2
Aluminum Selenide
Fe2S2

20. Common uses of polyatomics
acetate: C2H3O2- 
nailpolish
bicarbonate (hydrogen carbonate): HCO3- 
baking soda
chlorate: ClO3- 
detergents
cyanate: OCN- 
paper
cyanide: CN-
plastic
hydroxide: OH- 
water
nitrate: NO3- 
drinking water
perchlorate: ClO4- 
fireworks
carbonate: CO32-
glass
peroxide: O22-
mouthwash
sulfite: SO32-
wine
borate: BO33- 
wood preservatives
phosphate: PO43- 
dairy

21. polyatomic ions NH4+ ammonium ion NH3+ ammonia ion OH– hydroxide ion
CO3 2– carbonate ion
SO4 2– sulfate ion
CN – cyanide ion
NO3 – nitrate ion
PO43– phosphate ion

22. Nick the Camel ate a Clam for Supper in Phoenix
-Ates
Nick the Camel ate a Clam for Supper in Phoenix
Consonants = # of oxygens
Vowels = charge

23. Prefixes and suffixes Ion Name Ion Formula Meaning Persulfate SO52-
One more oxygen than Sulfate
Sulfate
SO42-
Most common ion
Sulfite
SO32-
One less oxygen than Sulfate
Hyposulfite
SO22-
One less oxygen than Sulfite

24. Polyatomic naming
The anion’s name ending remains (-ate, -ite, etc.), rather than changing to –ide.
You must have parentheses around the polyatomic ion if there is more than one.
All other ionic naming rules apply.

25. Practice Naming Polyatomics
NH4NO3
K3PO3
CsCO3
Al(OH)3
Fe2(SO4)3
Ba(NO3)2

26. Practice Writing Formulas
Lithium Phosphate
Barium Hydroxide
Magnesium Bicarbonate
Ammonium Phosphate
Potassium Chlorite