1. Simple Ion Review – Holt Section 1.
IONS
Simple Ion Review – Holt Section 1.

2. Key Terms
Octet Rule – The assumption that atoms are most stable with an outer valence shell of 8 electrons
Ion – a charged atom formed when an atom gains or loses electrons
Cation – An ion with a positive charge
Anion – An ion with a negative charge

3. Chemical Reactivity
An element’s reactivity depends on the amount and orientation of valence electrons.
The fewer electrons an atoms needs to gain or lose, the more reactive.
O example: 2 electrons needed for a stable octet and is more reactive than carbon who needs 4.

4. VIDEO EXAMPLES Sodium and Water Chlorine and Sodium
Magnesium and Oxygen

5. Reactive Elements
Noble gases have the most stable configuration. Notice this level has 8 valence electrons, making it most stable.
In chemical reactions atoms gain/lose electrons to have the same electron configurations to the stable noble gases.
Alkali Metals and Halogens are most reactive (see periodic table) because they have the least electrons to lose/gain to form a stable octet.

6. Types of Ions
Atoms who become an ion with a Positive Charge are called a cation.They lose electrons from their outermost energy levels to become positively charged. Metals tend to form cations.
An ion with a with a negative charge is called an anion. Anions gain electrons to become more negatively charged. Nonmetals tend to form anions.

7. Typical IonS Atom # Protons # Electrons Charge (#protons - #electrons)
Cation/Anion/Neutral Li 3 2
Cation F 9 10
Anion 8 Mg 12

8. Valence Electrons
An ion loses or gains electrons to form a stable octet.
Ions and noble gases can have the same amount of electrons and same configuration!
Example: K+ 18 electrons
Cl- 18 electrons
[Ar] 18 electrons

9. Characteristics/Properties
An ion has the same nucleus (number of protons and neutrons) as its parent atom, but a different number of electrons.
Chemical properties of an atom depend on number and electron configuration, so the ion has different chemical properties than its parent atom.
Example: Sodium ions do not react violently in water, because they have a stable noble gas configuration. Although stable, like the noble gas, the ions have electrical charge- allowing them to conduct electricity and form compounds.

10. Ionic Bonding/Salts
Holt. Chapter 5, Section 2.

11. KEY TERMS
Salt – An ionic compound that forms when a metal atom combines with a nonmetal.
Crystal Lattice – Regular pattern in which a crystal is arranged
Unit Cell – Smallest portion of a crystal lattice that shows the three- dimensional pattern of the entire lattice.

12. Ionic Bonding –
Ionic bonds are formed by the difference in charges between to ions. The positive ion is attracted to the negative ion.

14. Ionic Compounds
Ionic compounds, compounds formed by the bonding of positive cations with negatively charge anions, are called salts. Salts are electrically neutral compounds [NO CHARGE] Electrostatic forces are so strong, that each cation attracts several anions, pulling together into a tightly packed structure. Salts are made of several cations and anions bonded together in specific ratios.

15. Formation of ionic compounds
When the metal donates an electron, it forms a cation, and becomes smaller. When the nonmetal gains the electron, it forms an anion, and becomes larger.

16. Opposites Attract.
Large anions surround themselves with smaller cations, and cations attract anions forming a crystal lattice with repeating units.
Salts are made of unit cells (smallest repeating unit) that have an organized, tightly packed structure.
The crystal lattice arrangement will depend on the ratio of cations to anions, as well as, the relative sizes of cations to anions. Crystalline structures are 3D.

17. Properties of Ionic Compounds
- Ionic bonds usually form between atoms with large electronegativity differences.
- Ionic bonds are STRONG. There are large attractive forces between oppositely charged atoms in a crystal.
- Ions are tightly packed due to large attractive forces.
Solids at room temperature
High Melting Point
High Boiling Point
Hard and Brittle
Unable to conduct electricity in solid form due to limited movement
Ionic compounds have a neutral (0) overall charge.
*Dissolved ionic compounds and melted salts are great conductors of electricity as their charged particles can move freely.* Ionic compounds conduct electricity when dissolved in water!!

18. Ionic Formula writing/naming intro
Section 3.

19. Ionic Bonds
Ionic compounds or salts are formed from the attractive forces between ions.
Ionic compounds have a OVERALL NEUTRAL CHARGE
Ionic compounds are formed when atoms donate and accept electrons. Electrons are taken, not shared!
This means, the oxidation numbers of the cation and anion must cancel out when they form a salt.

20. Oxidation Number 2- 2+ Charge when atom becomes ion Examples: oxygen
Oxygen (2 electrons gained) 2-
Calcium (2 electrons removed) 2+
oxygen
Oxygen ion

21. Writing compounds 1. Use element symbols when writing compounds
Sodium: Na; Calcium: Ca
2. Use subscripts to communicate how many of each atom you have. Subscripts are numbers in the lower corner of the atomic symbol.
Example: Na2O
3. NO SUPERSCRIPTS (charges) in compounds. You do not need to write charges.
4. Use parenthesis if more than one group of atoms.

22. Ionic Compounds Examples:
Note: In both cases, the charges are not shown when writing the formula for the ionic compound!
In both examples, the cation and anion have equal/opposite charges which cancel out!
Ionic Compounds
Examples:
Calcium and oxygen
Ca2+ + O2-
CaO
Sodium and Chlorine
Na+ + Cl-
NaCl

23. Ionic Compounds
Note: In these examples, we must balance the charges of the cation and anion. They are opposite, but not equal!
Magnesium and Fluorine
Mg2+ + F-
MgF2
Barium and Nitrogen
Ba2+ + N3-
Ba3N2

24. Transition metals (d-Block)
Do not always have the same oxidation number.
Oxidation number (charge) is indicated by roman numerals in name.
Always cations, always positively charged.
Example:
Fe 2+ Fe 3+
Iron (II) Iron (III)

25. Examples of Common Transition metals…
Name
Symbol & Charge
Iron (II) and Iron (III)
Fe2+ , Fe3+
Copper (I) and Copper (II)
Lead (II) and Lead(IV)
Gold (I) and Gold (III)
Mercury(I) and Mercury(II)
Cobalt (II) and Cobalt (III)
Tin (II) and Tin (IV)
Chromium (II) and Chromium (III)

26. Naming Ionic Compounds
List the names of ions
CATION first, ANION last

27. Naming Ionic Compounds
CATION:
Use element name only!
i.e. Calcium 2+ ion = “calcium”
Transition metals have roman numerals as middle names to indicate their charge  Iron (II), Fe2+
ANION:
Change element ending to “ide”
i.e. oxygen 2- ion = “oxide”
i.e. Fluorine 1- ion = “fluoride”

28. Naming Ionic Compounds
We need to look at the overall charge of the anion to make sure we write in the correct cation charge!
Name this:
NaCl
Sodium chloride
Be3N2
Beryllium nitride
Fe3N2
Iron (II) nitride
Example: Nitride has a charge of -3.
There are 2 nitrides, so the overall charge of the anion is -6.
The overall charge of the cation must be +6. Because there are 3 irons, the charge of each iron atom is +2.
CuO
Copper (II) oxide
CoCl3
Cobalt (III) chloride