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

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

Separating the Weak from the Strong B Si Ge As Sb Te At

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!

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

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

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

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)

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!

Bonding Types Summary Metallic Ionic Covalent