1. Chemical Bonds, Nomenclature, Lewis Structure and Molecular Shapes
Chapter 5
Chemical Bonds, Nomenclature, Lewis Structure and Molecular Shapes

2. 75%
% Ionic Character
50%
25%
Electronegativity difference

3. I. Chemical Bonds B. Ionic Bonds
Know: Metals combine with nonmetals & form ionic bonds by losing or gaining electrons to mimic closest Inert Gas (VIIIA).
IA Na, K, Li, etc become +1 ions: Na+
IIA - Ca, Mg, etc become +2 ions: Ca+2
IIIA - Al, Ga become +3 ions: Al+3
VA - N, P become -3 ions: N-3
VIA - O, S become -2 ions: O-2
VIIA - F, Cl, Br, I become -1 ions: F-1
Opposite ions attract in a ratio so that the product is neutral.
Inert Gas e- Configurations

4. I. Chemical Bonds B. Ionic Bonds Example
Do not show charges in final formula. NaCl NOT Na+Cl-

5. I. Chemical Bonds B. Ionic Bonds Example

6. I. Chemical Bonds B. Ionic Bonds - Examples
Na+ + Na O Na2O
Ca F- + F CaF2
Mg S MgS
Al+3 + Al O-2 + O-2 + O-2 Al2O3
Give the formulas for the following: Na & Br
Ca & O Ba & I Li & O Al & F Mg & N
Many transition metals form ionic bonds & can have several charges such as Fe+2 = Iron (II) Fe+3 = Iron (III). Do not need to know these.

7. I. Chemical Bonds C. Electron Dot (Lewis) Strucures
- A Lewis electron dot structure is a symbol in which the valence electrons are shown as dots.
- Examples:
Na. Mg: Na+ Ca2+
H:1- (Called Hydride) :C: :Si:
- How many valence electrons (dots) would
N3- O2- F- or Ne have? What about Mg+2?

8. II. Covalent Bonds A. Introduction EN = electronegativity
- Definition of a covalent bond: A bond formed by the sharing of two electrons.
When two atoms of similar EN combine, neither has the “pull” to take electrons away & a sharing of electrons results.
This occurs when NONMETALS combine with NONMETALS. Note: H is a nonmetal.
Example: H. + H ) H—H = H2
- The atoms share valence electrons to get stable group VIIIA e- configurations.

9. II. Covalent Bonds A. Introduction
Covalent bond = sharing of 2 electrons.
2 shared electrons with (Single Bond).
4 shared electrons with (Double Bond).
6 shared electrons with (Triple Bond).
We frequently show the structure as a Lewis Structure - covalent bonds with lines and nonbonding valence electrons as dots.
- Note: Group IVA usually forms 4 bonds; VA three bonds; VIA two bonds; and VIIA (along with H) one bond.

10. II. Covalent Bonds B. Examples
H F::: ---) H F:::
H. + O H ) H O H
:N + N: ---) :N N:
:::Cl. + .O. + .Cl::: ---) :::Cl O Cl:::
::O: + :C: + :O:: ) ::O = C = O::

11. II. Covalent Bonds C. Lewis Structures 2. Examples
H I H2O NH4+
H2O CH4 SO2
AlCl NO CN-

12. Bonding Summary Two General Bonding Types
Ionic: Compound containing metallic element. Atoms lose/gain e to look like nearest inert gas. Add together ions such that neutralize charge.
Ia IIa IIIa Va VIa VIIa
2. Covalent: Compound containing nonmetals.
Atoms obtain inert gas configuration by
sharing valence electrons. : :: :::