1. No category

2.7 Ionic bonds are attractions between
ions of opposite charge
How is an ion formed?
When atoms gain or lose electrons, charged atoms called ions
are created
What causes an ionic bond?
An electrical attraction between ions with opposite charges
results in an ionic bond
The Formation of Sodium Chloride Salt
Na
Cl
Na
Sodium atom
Cl
Chlorine atom
+
–
Na
Cl
Na+
Sodium ion
Cl–
Chloride ion
Sodium chloride (NaCl)
all ionic compounds are called salts
Sodium Chloride Crystal
Na+
Cl-
Notice similarity between molecular level structure and actual crystal shape
(sharp edges)
2.8 Covalent bonds, the sharing of
electrons, join atoms into molecules
What do we call the sharing of electrons?
Some atoms share outer shell electrons with other atoms,
forming covalent bonds
Atoms joined together by covalent bonds form molecules
ionic bonds do not share electrons (one atom transfers an electron to the other)
Notice atoms are sharing electrons
A double bond is when two atoms share two pairs of
electrons
How many bonds do the Big Four Elements make?
HONC 1234
Hydrogen forms 1 bond
Oxygen forms 2
Nitrogen forms 3
Carbon forms 4
Methane, ball and stick model
Carbon is in the center making 4 bonds
Hydrogen on the sides making 1 bond each
Why will this formula not work? H-C=C-H
We need more Bond...
Each carbon needs to make four bonds.
Homework:
Read 2.9-2.10
Packet Exercise 5