1. Ms. Samayoa Chemistry Birmingham Community Charter High School
Covalent Bonds
Ms. Samayoa
Chemistry
Birmingham Community Charter High School
Warm-Up Question: What makes an ionic bond?

2. Learning Objective and Vocabulary
Learning Objective: Students will learn how to write covalent molecular compound names and formulas by completing a few problems through partner interaction. Academic Vocabulary Words: molecular compounds

3. REVIEW
In the previous lesson, we learned about electrons being transferred (either elements lost electrons or elements gained electrons)
This type of bond between a METAL and a NONMETAL is called an IONIC BOND, which results in a SALT being formed

4. COVALENT BONDS
In this lesson, you will learn about another type of bond in which electrons are SHARED
This type of bond is known as a COVALENT BOND
A COVALENT BOND are atoms held together by SHARING electrons between NONMETALS

5. What is a covalent bond?
A covalent bond is a bond between two NONMETALS
Remind them of hydrogen

6. Check for Understanding
Identify if the following compounds are covalent or ionic:
CaO
CO2
N2O3
MgO

7. Check for Understanding
Identify if the following compounds are covalent or ionic:
CaO – ionic
CO2 – covalent
N2O3 – covalent
MgO – ionic

8. How to Name Covalent Bonds
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
For the first element, start with the element name
For the second element, start with the –ide name
Use prefixes to show how many atoms of each type there are *DO NOT USE MONO- ON THE FIRST ELEMENT **IF YOU HAVE “AO” OR “OO,” TURN IT INTO “O.”

9. Naming Covalent Compounds - Example
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
SF6
N2O5
N2O3
P4S10
CF4
Do it on the board

10. Naming Covalent Compounds - Example
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
SF6 – sulfur hexafluoride
N2O5 – dinitrogen pentoxide
N2O3 – dinitrogen trioxide
P4S10 – tetraphosphorous decasulfide
CF4 – carbon tetrafluoride
Do it on the board

11. Write the names for the following compounds
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
P4S5 O2
SeF6
Si2Br6
SCl4
NF3

12. Write the names for the following compounds
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
P4S5 – tetraphosphorous pentasulfide
O2 – oxygen gas (dioxygen)
SeF6 – selenium hexafluoride
Si2Br6 – disilicon hexabromide
SCl4 – silicon tetrachloride
NF3 – nitrogen trifluoride

13. How to Write Covalent Molecular Formulas
Element
-ide Ending
Fluorine (F)
Fluoride
Chlorine (Cl)
Chloride
Bromine (Br)
Bromide
Iodine (I)
Iodide
Oxygen (O)
Oxide
Sulfur (S)
Sulfide
Nitrogen (N)
Nitride
Phosphorous (P)
Phosphide #
Prefix 1
Mono- 2
Di- 3
Tri- 4
Tetra- 5
Penta- 6
Hexa- 7
Hepta- 8
Octa- 9
Nona- 10
Deca-
Look at the element names and write it down
Look at the prefixes to learn how many atoms you have for each element

14. Write Molecular Formulas Example
chlorine dioxide
iodine pentafluoride
dinitrogen trioxide
phosphorus triiodide
Do on the board

15. Write Molecular Formulas Example
chlorine dioxide – ClO2
iodine pentafluoride – IF5
dinitrogen trioxide – N2O3
phosphorus triiodide – PI3
Do on the board

16. Practice Carbon tetrafluoride Silicon Dioxide Phosphorous mononitride
Nitrogen trifluoride
Boron trisulfide
Carbon tetrachloride

17. Practice Carbon tetrafluoride – CF4 Silicon Dioxide – SO2
Phosphorous mononitride – PN
Nitrogen trifluoride – NF3
Boron trisulfide –BS3
Carbon tetrachloride – CCl4

18. Covalent Bond and Lewis Dot Structures
Ms. Samayoa
Chemistry
Birmingham Community Charter High School

19. Learning Objective and Vocabulary
Learning Objective: Students will learn how to draw Lewis dot structures by drawing them for specific molecular compounds. Academic Vocabulary Words: Lewis Dot structures, molecular compounds, valence electrons

20. Review
How can we figure out the number of valence electrons an element has by looking at the periodic table?
Go over valence electrons and ionic charge on the periodic table

21. Lewis Dot Structures
In order to further understand ionic and covalent bonds, we need to learn how to draw Lewis Dot structures

22. To do Lewis Dot Structure we first need to….
Understand what electronegativity is
Electronegativity is…..
As we go across the periodic table (the same period), electronegativity (increases or decreases)?
As we go down a group, electronegativity (increases or decreases)?

23. Which element is more electronegative?
Na or S
K or Br
Li or Rb
F or Br

24. Which element is more electronegative?
Na or S – because sulfur has more protons
K or Br – because bromine has more protons
Li or Rb – because lithium has less shells (less electron shielding)
F or Br – because fluorine has less shells (less electron shielding)

25. Write the element in question and find out how many valence electrons it has
Atomic Symbol
# of valence electrons
Oxygen O 6
Fluorine
Nitrogen
Sodium

26. Board Problem
Examples: oxygen, fluorine, nitrogen, and sodium

27. Show second PowerPoint Presentation

28. Rules for Lewis Dot Structures
Find the total # of VALENCE electrons. - If there is a negative charge, ADD AN ELECTRON - If there is a positive charge, SUBTRACT AN ELECTRON
Decide the central atom - The central atom is usually the atom that is LEAST electronegative (except for H) - Occasionally, you will need to choose the unique atom
Connect the central atom with the outer atoms - Lines are known as “bonds” - Every bond counts for two electrons
Place remaining electrons on peripheral atoms and fill this atom up to 8 valence electrons

29. EXAMPLES
CS2
SCl4

30. If you need additional help…
How to Name Covalent, Molecular Compounds
How to Draw Lewis Dot Structures