1. Chapter 4 Chemical Bonds I:
The ionic bonds
Family – same # of valence (outer) shell electrons
Outer shell electrons are call valence electrons
For representative elements, valence electrons are outer s and
outer p electrons.
Group number = number of valence electrons

3. Lewis (electron) dot structure– shows the number of valence
electrons in an atom.
Figure Lewis Symbols for Selected Representative and Noble-Gas Elements

4. Compounds and Chemical Bonding
A compound consists of more than one element.
Elements combine to form compounds.
Example -
Na + Cl +
Na Cl
Cl + Cl Cl2
H + H H2
He, Ne, etc are stable
8 valence electrons (octet rule)
I. Ionic compounds
A. Formation of ionic compounds
Na + Cl

5. 2 Na 8 Cl 7 2 8

6. + - 2 Na 8 Cl 8 2 8
cation
anion
Octet rule

7. Mg + O ? Mg2+ + O Mg O Mg + O MgO Ca + Cl - Lewis structure2-
Mg + O ?
Mg2+ + O
Lewis structure Mg O
Mg + O
MgO
One formula unit
Ca + Cl 2+ - -
Lewis structure

8. Ca Ca P 3 2 2+ 3- 3 2 B. Properties of ionic compounds
High melting point
Conduct electricity when dissolved in water

9. Isoelectronic Species
C. Electron configuration of ions Na +
1s2 2s2 2p6
3s1 2+ Ca
Cl-
O2-
1s2 2s2 2p6 3s2 3p6
4s2
Isoelectronic Species
Example: Na O-2

10. Figure 4.5
Two-dimensional cross section of an ionic solid (NaCl). No molecule can be distinguished in this structure. Instead, we can recognize a basic formula unit that is repeated indefinitely.

11. Na+
Cl-
attractive force
Ionic bond
Fig. 4.1

12. NaCl (sodium chloride)
Na (sodium)
chlorine

13. D. Naming ionic compounds
a) Name of positive ions
1) monatomic positive ions – name of the element
Na sodium ion
K potassium ion fixed charge (Fig 4.8)
Ca calcium ion
etc.
Systematic name
Common name
Cu+ copper (I) ion cuprous ion
Cu2+ copper (II) ion cupric ion
Fe Iron (II) ferrous ion
Fe Iron (III) ferric ion

14. Figure A periodic table in which the metallic elements that exhibit a fixed ionic charge are highlighted.

15. 2) Polyatomic positive ions
ammonium ion
b) Negative ions
1) monatomic
2) polyatomic (Table 4.3)

16. Names of Selected Common Nonmetallic Ions.
Monatomic negative ions

17. Table 4.3
Common Polyatomic Ions.

18. c) Name and formula of ionic compounds
NaCl
sodium chloride
MgBr2
magnesium bromide
Mg Br-
ammonium sulfate

19. calcium nitrate
iron(II) phosphate
barium bisulfate

20. Use of noble gases
He balloon
Blimps – save
neon light
O2 + He for Scuba divers

21. Important ions in the body
Function
too much –
high blood pressure
Na+
outside the cell
regulation and control
of body fluids
regulation of body
fluids and cellular
functions K+
inside the cell
prevents high
blood pressure
Ca2+
outside the cell
90% in bone and
teeth
major cation in bone
Ca3(PO4)2, CaCO3.
regulate muscle
contraction
Lack – muscle
cramp, osteoporosis
Mg2+
Outside the cell
muscle and nerve
control

23. function
Cl-
Same as Na+
Fe formation of hemoglobin, enzyme, bind to O2
F tooth formation and retention of Ca2+ in bones
Cu2+ enzyme
Zn enzyme

24. In addition to the first 20 elements, memorize names and
symbols of the following elements
Cr Mn Fe Cu Zn
Mo Ag Cd
Pt Au Hg Pb
Sr Ba Br I
Zn2+ Cd2+ Ag+