1. Bonding Notes

2. An ion is an atom with a charge.
Which atoms form cations and which form anions?
H is not a metal !
NON-METALS
form ANIONS (-)
METALS
form CATIONS (+)

3. Ions form charges because
of their number of
valence electrons!!!

4. Valence electrons = are the electrons in the highest occupied energy level (s & p) of an element

5. Quick Trick for Valence e-
The group number tells the # of valence e--Group 1 (1A) has one valence electron
-Group 2 (2A) has two valence electron
Group 13 (3A) has three valence electrons
Group 15 (5A) has five valence electrons
Group 17 (7A) has seven valence electrons
Group 18 (8A) has eight valence electrons (except Helium which has two.

6. Na + Group number? 1A Electron configuration? 1s2 2s2 2p6 3s1 Period?
[Ne] 3s1
Valence electrons
Cation or anion (loss or gain of e-)?
[He] 2s22p6
Why?

7. Ca 2+ Group number? 2A Electron configuration? [Ar] 4s2 Period? 4
Valence electrons
Period? 4
Cation or anion (loss or gain of e-)?
[Ne] 3s23p6
Why?

8. S 2- Group number? 6A Electron configuration? [Ne] 3s2 3p4 Period? 3
Valence electrons
Period? 3
Cation or anion (loss or gain of e-)?
[Ne] 3s23p6
Why?

9. Practice
Page 9 charges of Ion Worksheet

10. Octet Rule = In forming compounds, atoms tend to achieve the electron configuration of a noble gas*

11. Octet Rule
Noble gas atoms are unreactive because their electron configurations are especially stable.
This stability results from the fact that the noble-gas atoms’ outer s and p orbitals are completely filled by a total of eight electrons.
Other atoms can fill their outermost s and p orbitals by sharing electrons through bonding.
Such bond formation follows the octet rule: Chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of electrons in its highest energy level.

12. Lewis Electron Dots
A visual representation of the valence electrons of the atom.
The inner electrons and the nuclei are represented by the element’s symbol.
The dots representing the electrons are arranged symmetrically around the symbol.
Chemical bonds are formed between atoms using the unpaired valence electrons.

13. We can represent the number of valence electrons in a pictorial representation called
Electron Dot Diagrams

14. Now you practice!!
Read the directions and complete the worksheet- pg 19 --Valence e- and the Periodic table worksheet

15. chemical bonds form electrical attraction.
A chemical bond is a mutual electrical attraction between the nuclei and valence electrons of different atoms that binds the atoms together
Ionic bonding:
Metal + Nonmetal
(Cation + Anion)
chemical bonds form electrical attraction.
atoms GIVE UP electrons to other atoms.
Form an “Ionic Compound”
Covalent bonding:
Nonmetal + Nonmetal
SHARING of electrons between atoms.
Form a “Molecular Compound”
Tricky—covalent bond but molecular compound!!

16. Ionic Compound Formula Unit (Example:NaCl)
Called Ionic bond & Ionic Compound
Made of metal and nonmetal (cation & anion)
Complete transfer of electrons
Na+ + Cl- = NaCl
electrically neutral salts -minerals in the earth’s
Formula Unit (Example:NaCl)
a chemical formula of the smallest sample of an ionic compound

18. Properties of ionic compounds
Crystalline solids (salts)
Ions sit ‘shoulder to shoulder’
High melting points (800ºC for NaCl-
hard to break bonds)
Conduct electricity
in solution
High boiling points
Break easily (brittle)
Many dissolve easily in water - ions separate

19. Ionic Bond =
Electrons are transferred from one atom to another.

21. Molecular Compounds/ Covalent Bonds

22. Molecular Compounds-Covalent Bonds
e- are shared between nonmetal atoms
Most atoms achieve complete octet

23. Properties of Molecular Compounds
Non-metal + Non-metal = covalent bond
2 non-metals SHARE e- to become stable like noble gases (think: hold hands)
low melting & boiling points (below 300ºC)
solid, liquid, or gas at room temp.
Molecular Formula:
carbon dioxide: CO2 & water: H2O
Molecules form shapes

24. Covalent Bonds
Covalent bonding—the sharing of electrons between two nonmetals. This creates a molecular compound or molecule.
The goal is to attain eight valence electrons—stability
Do not forget that hydrogen is a nonmetal.

25. Multiple Covalent Bonds
Single bond—formed when one pair of electrons is shared between two atoms.
Example H2
Double bond—involves two shared pairs of electrons.
Example Ethene C2H4
Triple bond—involves three shared pairs of electrons.
Example N2

26. Diatomic Molecules: atoms that bond with themselves
Nitrogen—N2
Oxygen—O2
Fluorine—F (All the halogens)
Chlorine—Cl2
Bromine—B2
Iodine—I2
Hydrogen—H2
Note: These molecules start with the atomic number seven & form the shape of the number seven on the PT. Don’t forget hydrogen in the upper left corner.

27. Practice Lewis Compounds
Ionic Bonding activity- page 20 & 21
Do page 20 together