1. Ionic and Covalent Bonds
Chapter 7
Ionic and Covalent Bonds

2. Review
Chemical Bonds form between 2 or more atoms to form molecules Two types of chemical bonds: Ionic Bonds & Covalent Bonds

3. Ionic Bonds & Covalent Bonds
Ionic Bonds- Electrons are transferred between a metal and a non-metal
Covalent Bonds- Electrons are shared between two non-metals
Remember: The “stairs” on your periodic table separate the metals and non-metals

4. In this Chapter…
You will understand HOW and WHY Ionic and Covalent Bonds form
To start- remember that an element becomes stable with 8 Valence Electrons
Hydrogen and Helium are exceptions, they only need 2 to be full
Atoms will give, take, or share electrons to get to 8 Valence Electrons

5. Electronegativity
Ability of an atom to gain an electron.

6. Electronegativity
When two atoms have a big difference in electronegativity the electron gets transferred
When there is a small difference the atoms share the electron
This is WHY the atoms form the type of bonds that they do

7. Ionic Bonds Form between a metal and a non-metal
There’s usually a big difference in electronegativity, which causes the metal to give its electrons to the non-metal
Example: K and O ( = 2.7 difference)
They transfer enough electrons so that both the metal and non-metal have 8 Valence Electrons

8. Ions When atoms give or take electrons they become charged Ions
Metals lose electrons to become cations (+)
Non-metals gain electrons to become anions(-)
Opposite charges attract, ions come together to form neutral molecules

9. Ion Formation To figure out what ion an element will form:
If it is a metal: Find out the number of valence electrons it needs to LOSE to get to zero.
Many Transition Metals can form more than 1 Ion
If it is a non-metal: Find out the number of valence electrons it needs to GAIN to get to 8
Hydrogen can both lose and gain 1 electron

10. Practice
For each element, find out the ion that it forms Chlorine: Beryllium: Argon:

11. Simple Ion Nomenclature (naming)
Simple cations are named by saying the element and adding the word “ion.”
Na+ is called “sodium ion”
Mg2+ is called “magnesium ion”
Simple anions are named by dropping the ending off the element name and adding “ide.”
F- is called “fluoride”
O2- is called “oxide”
N3- is called “nitride”

12. Practice
For each element, name the ion that it forms Chlorine: Beryllium: Argon:

13. Ionic and Covalent Bonds Day 2

14. Hydride AND Hydrogen ion H+ AND H- Helium He
Element
Symbol
Name
Formula 1
Sodium Na
Sodium Ion
Na+ 2
Bromine Br
Bromide
Br- 3
Magnesium Mg
Magnesium Ion
Mg2+ 4
Chlorine Cl
Chloride
Cl- 5
Oxygen O
Oxide
O2- 6
Boron B
Boron Ion
B3+ 7
Lithium Li
Lithium ion
Li+ 8
Neon Ne 9
Phosphorus P
Phosphide
P3- 10
Aluminum Al
Aluminum ion
Al3+ 11
Calcium Ca
Calcium Ion
Ca2+ 12
Iodine I
Iodide I- 13
Nitrogen N
Nitride
N3- 14
Cesium Cs
Cesium ion
Cs+ 15
Sulfur S
Sulfide
S2- 16
Fluorine F
Fluoride F- 17
Potassium K
Potassium Ion K+ 18
Barium Ba
Barium ion
Ba2+ 19
Hydrogen H
Hydride AND Hydrogen ion
H+ AND H- 20
Helium He

15. Ions Shortcut
Pull out your periodic tables! Group 1 = 1+ Group 2 = 2+ Group 13 = 3+ Group 14 = 4+ or 4- ***Depends on what it bonds with Group 15 = 3- Group 16 = 2- Group 17 = 1-

16. Simple Ionic Compounds
Ions come together to form neutral compounds
Today we will learn how to:
Write the chemical formula of the compound created
Figure out the name for the compound

17. Chemical Formulas of Ionic Compounds
We write chemical formulas of ionic compounds using the criss-cross method
With the criss-cross method you use the charge of the cation to figure out the subscript of the anion and vice versa

18. Criss - Cross Method
When possible, reduce the subscripts to get the most simple version of the chemical formula Situation 1: Ions with the same charge Mg2+ and O2- would be written as MgO, NOT Mg2O2 Situation 2: Any subscript with a 1 Mg2+ and Cl- would be written as MgCl2 NOT Mg1Cl2

19. Naming Ionic Compounds
When naming ionic compounds, simply write the element name of the metal followed by the ion name of the nonmetal.
The metal ion (cation) is always written first
The name of the metal is capitalized while the ion of the non-metal is not
NaCl is called “Sodium chloride”
CaCl2 is called “Calcium chloride”

20. Practice
Mg 2+ and Br - form what compound? Al 3+ and O2- form what compound?

21. Ionic Bonding Day 2.5

22. Today Mini-quiz: How to find Ions
Review how to write formulas for Ionic Compounds
Discuss how to name Ionic Compounds
WHY Ionic Bonds form the compounds they do
HW: Ionic Bonding WS

23. Mini-Quiz: Take out a half sheet of paper and your periodic table
What Ions do the following elements form? S Li Al Ne Br

24. Naming Ionic Compounds
Use the “Criss-Cross” Method to write ionic compounds:
If the charges have the same number, you do NOT write the subscript
If the number is a 1, you do NOT write the subscript

25. Practice- Take out your worksheet from yesterday
1. Na and Br: Na+ and Br- so NaBr
2. Ca and Cl Ca2+ and Cl- so CaCl2
3. Mg and S Mg2+ and S2- so MgS
Try #4 Al and O and #5 Li and P

26. Naming Ionic Compounds
When naming ionic compounds, write the element name of the metal followed by the ion name of the nonmetal.
NaCl is called “Sodium chloride”
CaCl2 is called “Calcium chloride”

27. Practice
11. K and O 12. Mg and I 13. Al and Cl Try #14 Ca and Br and #15 Na and N on your own!

28. Ionic Bonds Day 3 Polyatomic Ions

29. Polyatomic Ions
A polyatomic ion is made up of 2 or more atoms that are covalently bonded, but have an overall charge
Even though they are multiple atoms, we treat it like 1 ion
A list of polyatomic ions with their charges is given on your reference sheet– you need to keep this safe!

30. Polyatomic Ions in Formulas
Still use the same criss-cross method
Since the subscript applies to the ENTIRE polyatomic ion, the ion goes in ( ) with the subscript on the outside
Example: Mg and OH
Mg2+ and OH- form Mg(OH)2

31. Practice writing formulas
K and SO4 Al and NO3 NH4 and Cl

32. Naming polyatomic ions
Look up the name of the polyatomic ion using the polyatomic reference sheet
The regular ion uses the same naming as usual
Full name for Cation (+)
-ide ending for Anion (-)
Examples: Mg and OH Magnesium Hydroxide
Na and MnO Sodium Permanganate

33. Practice Naming
K and SO4 Al and NO3 NH4 and Cl

34. Ionic Bonding Day 4 Transition Metals

35. Transition Metals
Even though transition metals technically have 2 valence electrons, they don’t act like it Transition Metals can form a wide variety of cations We will use our reference sheet to see what ions the various transition metals can form

36. Figuring out transition metal charge
If the ion that goes with the metal does NOT have a subscript, then the metal has the same charge as the other ion AuCl = Au+ because Cl- FeO = Fe2+ because O-2 If the ion that goes with the metal DOES have a subscript, then the metal has the ion charge of the subscript AuCl3 = Au3+ Fe2O3 = Fe3+

37. Practice What is the charge on Zn in ZnCl2?
What is the charge on Cr in CrO?
What is the charge on Co in CoBr3?
What is the charge on Ni in NiSO4?

38. Figuring out ion charge without the formula
Without the formula given, you cannot know which ion charge to use (when there is more than one choice) When the formula is not given, you must write the formula for all possible ion choices Example: What is the formula for Cu and Cl? CuCl and CuCl2 are both the correct answer, you need both!

39. Practice
What are the possible formulas for… Fe and N? Ag and Br? Au and O?

40. Naming Transition Metals
Two types of names- standard and common name Standard name: Regular metal name with the ion number in roman numerals in parenthesis Example: Fe2+ Iron (II) Common name: Based on Latin Names Example: Fe2+ Ferrous Both are found on your transition metals reference sheet!

41. Practice
Name CuCl2 with both the standard and common names Name AuCl and AuCl3 with their standard names