Chapter 6: Chemical Bonding
Standards
• SPI 3221.1.4 Determine the Lewis dot structure
or number of valence electrons for an atom of
any main-group element from its atomic
number or position on the periodic table.
• SPI 3221.3.1 Analyze ionic and covalent
compounds in terms of their formation by
electrons, names, chemical and empirical
formulas, percent composition, and molar
masses.
Chapter 6
Section 1 Introduction to Chemical
Bonding
Ch. 6.1 Objectives
1. Define chemical bond.
2. Explain why most atoms form chemical
bonds.
3. Contrast ionic and covalent bonding.
4. Classify bonding type according to
electronegativity (EN) differences.
Chapter 6
Section 1 Introduction to Chemical
Bonding
Lesson Starter
• Imagine getting onto a crowded elevator. Many
people will experience a sense of being too close
together.
• When atoms get close enough, their outer
electrons repel each other. At the same time,
however, each atom’s outer electrons are strongly
attracted to the nuclei of the surrounding atoms.
• The degree to which these outer electrons are
attracted to other atoms determines the kind of
chemical bonding that occurs between the atoms.
Chapter 6
Section 1 Introduction to Chemical
Bonding
Chemical Bond
• Chemical bond- a mutual electrical attraction
between the nuclei and valence electrons of
different atoms that binds the atoms together.
– Most elements have higher energy while they are
lone atoms, they actually lower energy when they
bond as it fills their outer shell of electrons.
– Bonding makes most atoms happy and less
energetic.
Visual Concept
Chapter 6
Section 1 Introduction to Chemical
Bonding
Ionic Bonding
• Atoms prefer to gain or lose electrons to
become more stable.
– Forming cations or anions
• Ionic bonding- chemical bonding that results
from the electrical attraction between cations
and anions.
– Occurs between a metal and a nonmetal.
Visual Concept
Chapter 6
Section 1 Introduction to Chemical
Bonding
Covalent Bonding
• Covalent bonding- bonding resulting
from the sharing of electron pairs
between two atoms.
– Neither atom gains or loses, they both are
happy because they have a full outer shell
by sharing.
– Occurs between nonmetals.
– Why?
Visual Concept
Chapter 6
Section 1 Introduction to Chemical
Bonding
Comparing Polar and Nonpolar Covalent Bonds
• Ionic vs. Covalent depends on how strongly
each atom pulls on those electrons
(Electronegativity).
• To determine find the difference between the
electronegativities of both atoms.
• The difference will tell you if it’s an ionic or
covalent bond.
Visual Concept
Chapter 6
Section 1 Introduction to Chemical
Bonding
Using Electronegativity Difference to Classify Bonding
• If the difference is between 0-0.3 it’s a non-polar
covalent bond.
– Nonpolar covalent bond- a bond where the bonding
electrons are shared equally by the bonded atoms
(balanced charge).
• If the difference is between 0.3-1.7 it’s a polar
covalent bond.
– Polar covalent bond- a bond where there is an
unequal attraction for the shared electrons (uneven
distribution of charge).
• If the difference is between 1.7-3.3 it’s an ionic
bond.
Visual Concept
Chapter 6
Section 1 Introduction to Chemical
Bonding
Chemical Bonding practice
•Use EN values listed in Figure 20 on page 161,
and Figure 2 on page 176, to classify bonding
between sulfur, S, and the following elements:
1. hydrogen, H
2. cesium, Cs
3. chlorine, Cl
• In each pair, which atom will be more
negative?
Chapter 6
Section 1 Introduction to Chemical
Bonding
Chemical Bonding practice
•What type of bonding would be expected
between the following atoms?
a) Li and F
b) Cu and S
c) I and Br
• Which element would have the higher negative
character (EN)?
•HW: Please answer the objective questions for
this section and do the vocabulary for 6.2.