1. Let’s Make a Bond! How Do Atoms Get Stuck Together?
What do you think the word “bond” means in Chemistry?

2. Separating the Weak from the Strong
Nonmetals - Strong attraction for valence electrons
Metals - Weak attraction for valence electrons

3. Separating the Weak from the StrongB Si Ge As Sb Te At

4. Combining Atoms: Metal atoms only
Metallic Bonding – A bunch of metal atoms put their valence electrons in a shared pool. This is the “communist” bonding model.
Oh, Mg!

5. Nucleus and core e- are fixed
Basic metallic bonding model
e- free to move around
Sea of shared electrons
Zinc metallic nucleus

6. Combining Atoms: Metal and Nonmetal
Ionic Bonding – Nonmetal atoms are the bullies. They steal valence e- from metal atoms. Metals are the push overs. They let the nonmetals take them.
Nonmetals become anions (negative ions) and metals become cations (“paws” – tive). And opposites attract!
This forms the “ionic lattice”
Nonmetals = bullies

7. Ionic bonding of NaCl
Na+ = metal
Cl- = nonmetal
Space filling model of NaCl

8. The octet rule
In stable compounds, atoms tend to from ions with 8 valence electrons (full valence energy level).
Ex. Cl has 7 valence e- , so it gains 1 more
Ex. Na has 1 valence e- , so it loses 1 e- (leaves 8 valence e- in lower energy level)

9. Combining Atoms – nonmetals only
Covalent bonding – 2 atoms at a time share a pair of valence e-
Neither partner will let go of the electrons
Atoms are stuck together
When two or more atoms covalently bond together, they make a MOLECULE!!!!!
Ex. Water!

10. Bonding Types Summary
Metallic
Ionic
Covalent