Chemistry Bonds Ionic Bonding: electrostatic attraction. **Electron Configuration **Orbital Diagrams **Dot Diagrams **Periodic Trends

Properties of Ionic Compounds Cations are positive ions. Always written first. Anions are the negative ions. Written after the cation Positive and negative ion pack in a regular pattern that balances the forces called an ionic crystal or crystal lattice. Form 3-D compounds High melting and high boiling point. Compound defined by hardness and brittle. Almost always exothermic when bond is broken. Lattice energy defines the strength of the ionic bond.

Properties of Ionic Compunds Further separation on the periodic table, the MORE ionic characteristics. Conductive current dissolved and melted state Ionic compounds are referred to as formula units (FU). Net charge of the compound must = zero, Σ+ = Σ-

Formation of Ionic Bonds Balance in the net charge: *Net charge must be ZERO. *Criss-Cross method to balance charge. **Assigning oxidation numbers **Roman numeral is the oxidation number *Metals or positive ion always written first. *An ionic compound is called a formula unit. *Binary : made up of two particles, + and - . *Ternary: made up of two particles, + and – in which one is a polyatomic ion.

Formation of an Ionic Bond Assign oxidation number. Review periodic trends: Group 1A = 1+ Group 2A = 2+ Al = 3+ Oxygen 2- Group 7A = 1- Transitional Metal commonly = 2+ Cu , Ag, Au commonly 1+

Also Names for Cations (Metals) Iron Ferrous (Fe2+) Ferric (Fe3+) Copper Cuprous (Cu1+) Cupric (Cu2+) MercuryMercurous (Hg1+) Mercuric (Hg2+) Lead Plumbous (Pb2+) Plumbic (Pb4+) Tin Stannous (Sn2+) Stannic (Sn4+) *******Criss-Cross Method*******

Sample Compounds: 1. Use orbital diagrams to show how the following combine: Na and Br Al and S K and S 2. Now use the criss-cross method to show how the charges balanced in the above compounds. (positive ion always first).

Writing Formula Unit from Name Define if the name is of a binary or ternary compound. Binary anion ends in –ide. Write the symbol for the element (metal first) Assign oxidation numbers. Criss-cross Assure that the net charge of the FU is zero With transitional metal: The Roman numeral is the oxidation number for the metal.

Practice Problems Write the formula unit for the following: a. potassium and iodide b. magnesium and chloride c. aluminum and bromide d. cesium and nitride e. barium and sulfide f. iron and oxygen

Practice Problems Write the following ionic compounds: a. Ferric oxide b. Stannic fluoride c. Cuprous oxide d. Plumbic oxide e. Mercurous bromide f. Ferrous oxide

Polyatomic Ions Covalently bonded particles with a charge: **Table 7.9 or reference sheet. **Forms ionic compounds **Criss-Cross method, net charge is zero **Patterns in naming. **First name is the name of the element. **Second name is the name of the polyatomic ion. **More than one poly, put in parenthesis.

Sample Compounds Write the compound for the following ions: Al to SO4 NH4 to PO4 Mg to NO3 Al2(SO4)3 (NH4)3PO4 Mg(NO3)2

Naming Binary Ionic Compounds First name is the name of the cation (metal). Second name is the name of the anion or non-metal with the ending dropped and the suffix –ide added. You see –ide then = binary except for bisulfide, cyanide, hydroxide, NaCl BaS CaBr2

Naming Ternary Ionic Compunds First name is the name of the element or the polyatomic ion. Second name If the anion is an element, then add –ide. If the anion is a polatomic ion, then the name is the name of the poly ion.

Writing Formula Unit from Ternary Name Identify if the name is of a binary or ternary compound. Ternary anion ends in –ite or –ate. Note exception of hydroxide, cyanide, bisulfide. Write the symbol of the elements and/or polyatomic ion Assign the oxidation number. Criss cross More than one poly put parenthesis Assure the net charge is zero.

Naming Ionic Compounds Binary Ionic Compounds: Single cation to anion. NaCl K2S MgO Ternary Ionic Compounds: Combination of anions and cation along with polyatomic ions. K2SO4 NaHCO3 (NH3)2SO4

Writing and Naming Acids/Bases Binary Acids Hydrogen is always written first Balance charge to = zero Hydro – root or the anion – ic acid HCl H2S HF HBr HI

Writing and Naming Acids/Bases Ternary Hydrogen is always written first Followed by a polyatomic ion NO Hydro- prefix Poly name follows; -ate –ic ; -ite –ous H3PO4, H2SO3, HClO3, HNO2

Writing and Naming Acids/Bases NH3 Identify by the OH anion First name is the name of the element. Second name is hydroxide NaOH, Ba(OH)2, LiOH, Fe(OH)3

Oxyanion or Oxides Polyatomic ions that contain oxygens. Name based on the number of oxygens present. Chlorate ClO3- One less than –ate is –ite; chlorite ClO2- Two less than –ate is hypo- root-ite; hypochlorite ClO- One more than –ate is per-root-ate; perchlorate ClO4- ****The charge NEVER changed*****

Metallic Bonds/Properties Metallic bonds, electrons are shared between metal atoms. Free electron called delocalized electrons. Sharing make metallic bonds: Flexible Ductile Malleable High melting point High boiling point Good conductors of heat and energy

Molecular Formulas Bonding of element with a small difference in electronegativity. ***Usually non-metal bonded to non-metal*** Writing and naming: 1. Use of prefixes to indicate the number of each element in the molecule. 2. Follow the same standards as in the naming of formula units.

Molecular Formulas Prefixes: mono- for one (used w/ the second name usually) di- for 2 hexa- for 6 tri- for 3 hepta- for 7 tetra- for 4 octa- for 8 penta- for 5 nano- for 9 deca- for 10

Molecular Formulas N2O5 Dinitrogen pentoxide CCl4 Carbon tetrachloride Silicon dioxide SiO2 Diphosphorous hexaflouride P2F6