1. Ch. 7 Ionic Bonds

2. Chemical Bonds
Chemical bonds form when atoms are strongly attracted to one another
Ionic Bond
Covalent Bond
Metallic Bond

3. Compounds - Review
Compound: Substance that is composed of two or more elements that are combined chemically
Properties of a compound are generally very different from the elements that make it
Chemical Formulas:
Formulas show the symbols on the ration of the elements in the compound
Subscripts: tell the number of each element in the compound
Ex. C12H22O11

4. Review: Valence Electrons: Electrons in the highest energy level
The number of valence electrons largely determines the chemical properties of an element.
To find the number of valence electrons, look at its group number.
Electron Dot Notation: represents the number of valence electrons

5. Ions - Review
Ion: an atom or bonded group of atoms that has a positive or negative charge
When atoms lose electrons and become positive ions, they always become smaller (compared to the neutral atom)
Loss of valence electron can leave an empty outer orbital resulting in a small radius
When atoms gain electrons and become negative ions, they become larger

6. Octet Rule
Atoms tend to gain, lose (ionic bond) or share (covalent bond) electrons until they are surrounded by eight valence electrons
An octet consists of 8 valence electrons
Since the noble gases have eight electrons, we assume that an atom is stable when surrounded by 8 valence electrons

7. A gain of one electron gives chlorine an octet and converts a chlorine atom into a chloride ion. It has the same electron configuration as the noble gas argon.

8. Ionic Bond Type of chemical bond
Electron transfers lead to forces holding atoms together
Binds opposite charged ions together
Formed by a METAL and a NONMETAL (or a group)
Examples: NaCl (Sodium Chloride), Na2CO3 (Sodium Carbonate)
**To determine is an element is a metal, nonmetal or metalloid, look at its placement on the periodic table.

9. Ionic Bonding
A bond forms when oppositely charged atoms are electrostatically attracted to one another as a result of the transfer of electrons

10. Classes of Ionic Bonds Oxides Salts
Compounds with ionic bonds between a metal and oxygen
Example: MgO (Magnesium Oxide)
Salts
Generic name for most ionic compounds
Examples: NaCl (Sodium Chloride), ZnI2 (Zinc Iodide)

11. Intro to Ionic Names & Formulas
Monatomic Ions: one-atom ions
Cation
Positive ion formed by the loss of valence electrons
Atom loses electrons to have an octet like the previous noble gases
Naming: The cation name stays the same as the atom name
Example: Li  Lithium
Li+  Lithium Ion

12. Monatomic Ions 2) Anion A Negative ion formed by the gain of electrons
Atoms gain electrons to achieve an octet
Naming: For the anion, add the suffix –ide to the root of the atom name
Example: Br bromine, Br -  Bromide Ion

13. Oxidation Number (Oxidation State)
The charge of a monatomic ion
The number of electrons gained or lost to make an ion
Monatomic Ion Trends:
Group 1: Plus 1 charge
Group 2: Plus 2 charge
Group 17: Negative 1 charge
Group 16: Negative 2 charge
Group 15: Negative 3 charge

14. Practice:
Write the symbol, name of the ion, and determine if it’s a cation or anion.
An iodine atom gains one electron
A strontium atom loses two electrons
A sulfur atom gains two electrons
An aluminum atom loses three electrons

15. Practice:
Atoms that tend to gain a noble gas configuration by LOSING valence electrons are A. Metals B. Nonmetals C. Noble Gases D. Representative Elements

16. Polyatomic Ions Polyatomic Ions: Ions made up of more than one atom
Charge applies to the whole group
Never change the subscripts of atoms within the ion
Example: CO32- (Carbonate)
Oxyanion:
Ion with a nonmetal and one or more oxygen atoms

17. Polyatomic Ion Trends
Naming Element: S Sulfur Anion: S2- Sulfide SO52- Persulfate (+1 oxygen) SO42- Sulfate SO32- Sulfite (-1 oxygen) SO22- Hyposulfite (-2 oxygen)

18. Ionic Bonds Ion Bond: Metal and Nonmetal Or
Positive Ion and Negative Ion
When atoms transfer electrons, the atoms become bonded and form ionic compounds
Although they are composed of charged ions, ionic compounds are electrically neutral (positive charge = negative charge).

19. Ionic Nomenclature Writing Ionic Compound Formulas:
Write the cation and anion formulas with charges
Balance the charges with subscripts if necessary
Use parentheses around polyatomic ions that need a subscript added
Write the final neutral formula without charges

20. Practice: Potassium Permanganate: Aluminum Oxide:
K+ MnO4-  KMnO4
Aluminum Oxide:
Al3+ O2-  add Al3+ Al3+ O2- O2- O2- Al2O3
Copper (II) Hydroxide:
Cu2+ OH-  add OH-  Cu(OH)2

21. More Practice: Sodium Phosphate: Iron (III) Sulfate:
Calcium Manganate:
Na3PO4
Fe2(SO4)3
CaMnO4

22. Naming Ionic Compounds
Cation name written first
Anion name written second
**Reminder: Use the roman numerals for most cations

23. Practice:
Li3PO4 -- lithium phosphate
Fe(ClO4)2 -- iron (II) perchlorate
Na2SO4 – sodium sulfate

24. More Practice:
(NH4)2S
AgC2H3O2
CuCl
LiHCO3
Ammonium Sulfide
Silver Acetate
Copper (I) Chloride
Lithium Bicarbonate

25. Properties of Ionic Compounds
Crystal Lattice:
Ions are arranged in a regular, repeating 3D pattern
Each +ion is surrounded by – ions
Overall the shape of the crystal depends on the relative number of + ions and – ions

26. Crystal Structure

27. Properties of Ionic Compounds
Physical Properties:
Particles are highly attracted to one another
High melting & boiling points
Ionic crystals are hard, rigid, and brittle
Can conduct electrical currents
Electrolyte: an ionic compound whose aqueous solution conducts electricity
Aqueous Solutions: A substance dissolved into water