1. Chapter 7: Ionic Bonding & the Formation of Ionic Compounds

2. Matter is made of Atoms!

3. Nothing would “matter” without “Atoms”

4. Atoms can bond together . . .

5. Types of Bonds
Oh yeah, these too. . .
Covalent Bond
Ionic Bond

6. Chemical Bonds
Chemical compounds are divided into two broad classes called ionic compounds and molecular compounds
Ionic compounds tend to have high melting points and are good conductors of electricity - when melted or dissolved only
Molecular compounds, generally have lower melting points and can be gases, liquids, or low-melting solids at room temperature.  They are poor conductors of electricity.

7. Chemical bonds - the attractive forces that hold atoms together
Ionic bonds - the transfer of electrons from one atom or group of atoms to another.
Covalent bonds - the sharing of one or more pairs of electrons between atoms.

8. Two fundamental concepts that are common to both the ionic and covalent bonding models: 
1.  Not all electrons in an atom are available for bonding. Those that are, are called valence electrons.
2. Certain arrangements of electrons are more stable than other arrangements.  (Can you guess which ones?)

9. Valence Electrons and Electron-Dot Structures
Valence electrons are all those electrons in the outermost electron level, that is, in the shell with the highest shell number.  
Determine the number of valence electrons present in:
Mg Cl Se
Next page please…

10. Mg has two valence electrons
You could have just looked at the element's group number!

11. Cl has seven valence electrons

12. 6
Se has six valence electrons.
                                                     
This is too easy!

13. Electron-Dot Structure
A shorthand system for designating numbers of valence electrons uses electron-dot structures
An electron-dot structure consists of an element's symbol with one dot for each valence electron placed about the elemental symbol. 
Electron-dot structures are also called
Lewis dot structures

14. Mg 2 → How many valence electrons are in Mg?
Electron Dots = Valence Electrons
Symbol = inner electrons & the nucleus
Each position (up, down, right, left) around the element symbol represents an _____________, which can hold no more than _________ electrons.
orbital
two

15. Lewis Dot Diagrams of Selected Elements
                                                                                                       

16. H Cl Typically, an element in group: one 1A forms ___________ bond
2A forms ___________ bonds
3A forms ___________ bonds
4A forms ___________ bonds
5A forms ___________ bonds
6A forms ___________ bonds
7A forms ___________ bond H
two
three Cl
four
three
two
one

17. Electron-Dot Structures
Hydrogen
Oxygen
Chlorine

18. Important Generalizations
1.  Representative elements in the same group of the periodic table have the same number of valence electrons.
2.  The number of valence electrons for representative elements in a group is the same as the periodic table group number.
3.  The maximum number of valence electrons is eight.

19. Is there a specific way the electrons dots are arranged around an element?
As long as there are no more than 2 electron dots per side you are O.K.
NO!
Draw the electron dot structure for the following elements:
Lone pairs - electrons that typically are not shared during bonding. P K
Unpaired electrons - participate during bonding. Cl

20. Draw electron dot structures for:Mg S Br

21. The Octet Rule
A key concept is that certain arrangements of valence electrons are more stable than others.  
The outer shell electron configurations possessed by the noble gases (He, Ne, Ar, Kr, Xe, and Rn) are the most stable

22. For helium, this most stable electron configuration involves two outer shell electrons.  The rest of the noble gases have eight outer shell electrons.
He: 1s2
Ne:  1s2 2s2 2p6
Ar:  1s2 2s2 2p6 3s2 3p6
Octet Rule: In forming compounds, atoms of elements lose, gain, or share electrons in such a way to produce a noble gas electron configuration.

23. The Ionic Bond Model
Compounds can be formed from the combination of a negative ion and a positive ion. 
Such compounds are called ionic compounds. 
The negative and positive ions of the compound are held together by an ionic bond.

24. Use the electron dot structure to show how Na can become an ion:
Sodium atom (electrically neutral, i.e. charge = 0 ) →
Loses one electron
[Na]+
Sodium Ion (charge = +1) + e- 1
electron

25. Use the electron dot structure to show how Mg can become an ion:+
2e-
2 electrons Mg
Mg atom (electrically neutral: charge = 0) →
Loses 2
electrons
[Mg]2+
Mg Ion (charge = 2+)

26. Use the electron dot structure to show how Cl can become an ion:
Cl atom (electrically neutral: charge = 0)
Cl ion
(charge = -1) Cl ] [ -1 →
Gains 1
electron e- +

27. [ ] [ ] The Ionic Bond Model Example - Show the formation of Na2O:
       
Na2O [ ] [ ]

28. Show the formation of CaCl2+ [ ]

29. Show the formation of the following ionic compounds using electron-dot structures:
a)  K3P b) NaF
c)  Al2O3 d) KF
e)  Li2O f)  Ca3P2

30. Exceptions Continued:
Ni:
[Ar] 4s2 3d8
Ni+2:
[Ar] 3d8
Fe:
[Ar] 4s2 3d6
Fe+2:
[Ar] 3d6
[Ar] 3d5
Fe+3:

31. Let’s Review . . .
WAKE UP

32. lose
gain
A. Atoms will _________ or _______ electrons to become like the nearest _____________ gas, which has ______________ valence electrons or a full __________________.
noble
eight
octet
→ Octet rule: Atoms will lose or gain electrons to have a stable electron structure; like a noble gas that has eight valence electrons.
compounds
Elements will also form _________________ to become stable & share or steal each other’s electrons to have a full ____________.
octet
Atoms will form octets in their ____________ existing or remaining energy level.
highest

33. → Halogens will gain one electron & become a ______________ ion.
metallic
1. Cations are ______________ elements that will ________ their valence electrons to become stable & obey the octet rule.
lose
nonmetallic
2. Anions are ______________ elements that will ________ their valence electrons to become stable & obey the octet rule.
gain
→ Halogens will gain one electron & become a ______________ ion.
halide

34. Ionic Bonds
anions
A. Ionic bonds are formed between __________ & ______________ which are held together by ___________________ forces.
cations
electrostatic
lost
B. A cation has ______________ its electron & an anion has ________________ an electron.
gained
C. In ionic bonds, the elements do not share their electrons but ___________________ their electrons.
transfer or steal