Bonding Ch 7 8 Ionic Need to know

Bonding Ch 7 & 8

Ionic • Need to know – Valence electrons – Octet rule – Cations – Anions – Ionic compounds • Obviously, you need both a cation and an anion to create one of these…remember, net charge = 0.

Ionic compounds • Chemical formula: the kinds and #s of atoms that make up the smallest unit of a substance/cpd. • Formula unit: lowest whole number ratio of the atoms making up a cpd. • Properties: brittle, crystalline solids, generally high melting pts. , • Coordination number: # of atoms of opposite charge that surround an ion in the crystal structure • Ionic cpds. will conduct a current

Metallic bonds • Free sea of electrons…this is what allows the ductile and malleable nature to occur. • 202: body-centered, face-centered, hexagonal close packed xl structures. • Alloys: solutions

Molecules and cpds. • Covalent bonds: sharing electrons to satisfy the octet rule. Again, remember, net charge =0. • Diatomic molecule: molecule with 2 atoms. • Diatomic elements: H, N, O, F, Cl, Br, I. • Molecular cpds: lower MP & BP.

Molecular Formulas • How many atoms of each element in a molecule of a given compound

Bonds • Single bond: the sharing of 2 (aka 1 pair) of electrons between 2 atoms. • Double bond: the sharing of 4 (aka 2 pairs) of electrons between 2 atoms. • Triple bond: the sharing of 6 (aka 3 pairs) of electrons between 2 atoms. • No, no quadruple bonds…sorry.

More on bonds • Sigma and pi bond discussion: 230 -231 • VSEPR: valence shell electron pair repulsion theory: orbitals hybridize as needed for capacity for electrons. 232 -236