1. Chapter 5 Atoms and Bonding DO NOW:
1. Make a cover page in your NB for Chapter Draw a Bohr diagram for sulfur. 3. How many valence electrons does sulfur have?
Chapter 5
Atoms and Bonding

2. Do Now: Draw a Bohr diagram for sulfur
Do Now: Draw a Bohr diagram for sulfur. How many valence electrons does S have?
Elements
1st level = 2
2nd level = 8
3rd level = 8
4th level = 2
Electron
Shell
Capacities:
16 P
16 N
Elements 21 – 112
1st level = 2
2nd level = 8
3rd level = 18*
4th level = 32*
5th level = 32*
*sub-levels exist
Sulfur
16 electrons
6 valance electrons

3. All atoms want to achieve a full octet; which means they have a full outer valence shell
Neon
10 electrons
8 valence electrons Ne

4. Why Do Valence Electrons Matter?
The valence electrons show WHY certain elements bond with other elements to form compounds. H H S
Sulfur’s 6 valence electrons WANT 2 more electrons
2 Hydrogen atoms will make 8 total

5. Remember, the # of valance electrons matches its family #
Alkaline Earth Metals
Alkali Metals
Nitrogen Family
Oxygen Family
Carbon Family
Halogens
Noble Gases
Boron Family
Transition Metals
*Matches 2nd digit groups

6. Electron Dot Diagrams AKA Lewis Structure
Symbol of an element surrounded by “dots”.
Each dot represents one valence electron.

7. Electron Dot Diagrams AKA Lewis Structure
The Element Symbol serves as the representation of the nucleus. C

8. Electron Dot Diagrams AKA Lewis Structure
Dots are added at 12 o’clock, 3 o’clock, 6 o’clock, and 9 o’clock. C
Carbon has only 4 electrons in the 2nd energy level so we need only represent those 4

9. Electron Dot Diagrams AKA Lewis Structure
Only valence electrons are shown.
Maximum of 8 dots (electrons)

10. Draw Electron Dot Diagrams for
Lewis Structure Practice
Oxygen
Group =
Valance electrons =
Chlorine
Group =
Valance electrons = 16 17 6 7 O Cl
Draw Electron Dot Diagrams for
Beryllium and Sulfur

11. To Become Stable Atoms… They Bond
Beryllium = Group 2
= 2 valance electrons
Sulfur = Group 16
= 6 valance electrons

12. Chemical Bonds
Atoms with unfilled valence shells are considered unstable.
Atoms will try to fill their outer shells by bonding with other atoms.
The number of valence electrons will determine how many bonds the atom can form.
A chemical bond is the force that holds the molecules together
Two types of bonds we will discuss:
Ionic bonds
Covalent bonds

13. Chemical Bonds are represented with Chemical Formulas
Understanding chemical formulas:
BaF2
Subscripts: tells how many atoms of that element are in the compound
refers only to the element preceding it
The subscript 2 in this formula is for the F (fluorine)
Ba (barium) only has one atom (1’s are not written)

14. Al(NO3)3
Parentheses: The subscript outside the parentheses refers to all the elements inside the parentheses
Multiply the subscript outside with each subscript inside to get the total number of atoms
In this example there are: one Al (aluminum), three N (nitrogen), and nine O (oxygen) atoms
3BaF2
Coefficients: refers to each element that follows
Multiply the coefficient with all subscripts
The 3 in this example means there would be
3 Ba (barium) and 3 F2 (a total of 6 fluorine) atoms

15. Identifying and Counting Atoms
in a Chemical Formula

16. Try It: Count the Atoms in each Chemical Formula

17. Try It: Count the Atoms in each Chemical Formula1 12 6 1 2 42 24 1 1 6 4 22 21 9 4 6 12

18. Back to Bonding…

19. Valence Electrons Determine
Oxidation Numbers +1 +4 -4 +2 +3 -3 -2 -1

20. Oxidation Numbers
Shows the number of electrons an atom will gain, lose, or share.
Positive (+) or negative (-) number assigned to an element.
Comes from its family number on the Periodic table
Metals (Families 1, 2, 13  +1, +2, +3)
Nonmetals (Families 15, 16, 17  -3, -2, -1)
Noble Gases (Family 18  0)
Transition metals have various oxidation numbers between 1 and 4

21. +1 +4 -4 +2 +3 -3 -2 -1

22. Atoms that are no longer neutral are called ions
An atom or groups of atoms that have lost or gained electrons
Atom becomes either negatively (-) or positively (+) charged
Change occurs since the ratio of protons to electrons is not equal

23. Ions form from atoms who gain or lose electrons

24. When an atom loses an electron it becomes positively charged
Cation: positive ion
When an atom loses an electron
it becomes positively charged
Ex: Calcium ion = Ca+2
Anion: negative ion
When an atom gains an electron
it becomes negatively charged
Ex: Fluorine ion = F–
(the 1 is inferred)
Oxygen at the Playground

25. Polyatomic Ions + Ions that stay together as a group ammonium nitrate
Poly- ionic name: ammonium nitrate +

26. Polyatomic Ions + Ions that stay together as a group ammonium nitrate
Poly- ionic name: ammonium nitrate +

27. Time to Bond Ions Each index card represents either a cation (+) or an
anion (-)
Any opposite charged ions can bond
Writing the chemical formula and names:
1. Oxidation numbers will become subscript numbers for the opposite element
2. Write both element names, but change the second element ending to “ide”
Oxygen at the Playground

29. Ionic Bonding How does it work?
Ionic bonding takes place between metals and non-metals.
In an ionic bonds :
oppositely charged ions (+) and (-) attract
electrons are transferred
Ex. NaCl (Na +1 Cl -1)

31. Naming Ionic Compounds
Name of the + ion comes first, and - ion comes second
Metal + Nonmetal
Monatomic ions: change nonmetal ending to –ide
Ex: Mg F -1 becomes
MgF2 or Magnesium Fluoride
Polyatomic ions: change nonmetal ending to –ate
or –ite
Ex: NaNO3 = sodium nitrate
Mg3(PO4)2 = magnesium phosphate

32. I I Mg Do Now Magnesium +2 Iodine -1 1. Draw the Lewis structure for:
2. Write the chemical formula these two ions would create
MgI2 (Magnesium Iodide)
3. What type of bond would these 2 atoms make?
Ionic since Magnesium is Metal and Iodine is a Nonmetal I I Mg

33. Covalent Bonding H O H Occurs between two nonmetals
Electrons are shared instead of being transferred
Both atoms need to gain electrons, so they share the electrons they have.
Atoms still follow the octet rule
No ionic charges or oxidation numbers
Sharing
electron H O H
Sharing
electron - - - + - - + + - - - - -

34. How Covalent Bonding Works
Electrons move back and forth between the outer energy levels of each atom.
Each atom has a stable outer energy level some of the time.
Atoms can share one, two, or three pairs of electrons.
BrainPop Bonding
Bonding Animation

35. Carbon Dioxide (CO2) Water (H2O) Nitrogen (N2)
Double Bonds Share 4 Electrons
Triple Bonds Share 6 Electrons
Single Bonds Share 2 Electrons

37. Naming Covalent Compounds1
mono 2 di 3
tri 4
tetra 5
penta 6
hexa 7
hepta 8
octa 9
nona 10
deca
Each element gets a “greek prefix”
Prefix refers to # of atoms in the molecule
Change ending to “ide”
Ex: N2O4 = dinitrogen tetroxide
The first vowel is often dropped to avoid the combination of “ao” or “oo”.
octaoxide = octoxide
Exception: drop mono for first element
CO2 = carbon dioxide
CO = carbon monoxide

38. NOW do you find this funny?!

39. Try This: CCl4 P2O3 IF7 CCl4 = carbon tetrachloride
Name these covalent compounds:
CCl4 P2O3 IF7
CCl4 = carbon tetrachloride
P2O3 = diphosphorus trioxide
IF7 = iodine heptafluoride

40. Try This: Write the covalent compound formula: Tricarbon pentoxide
Sulfur nonafluorine
Tricarbon pentoxide = C3O5
Sulfur nonafluorine = SF9

41. Candy Bonds Activity

43. Today’s Agenda Candy Bonds activity
Discuss/Correct HW worksheets from last week:
Elemental Love Story
Naming practice
Complete Chapter 5 review worksheet
Check answers in back- flower folder
Share Answers to Candy Bonds
* If time: Draw Your Own- plain white paper

47. 1. What type of bond occurs between a metal and a nonmetal? ionic
2. What type of bond occurs between a two nonmetals? Covalent
3. CaF2 Calcium fluoride (*ionic)
4. triphosphorus tetrabromide P3Br4
5. N5O9 Pentanitrogen nonoxide

48. Solutions: Name these compounds: CCl4 = carbon tetrachloride
P2O3 = diphosphorus trioxide
IF7 = iodine heptafluoride
Write these compounds:
Tricarbon pentoxide = C3O5
Sulfur nonafluorine = SF9
What Kinds of Bonds are These?

49. Sodium Chloride = NaCl = Na+1 + Cl-1
Ionic Bonding
Sodium Chloride = NaCl = Na+1 + Cl-1