Multiple Covalent Bonds

Multiple Covalent BondsA covalent bond can share more than one pair of electrons. Example: Nitrogen that exists in the atmosphere is N2

Unequal Sharing of ElectronsIn a water molecule, oxygen pulls the electrons more strongly than the hydrogen atoms do.The electrons spend more time around the oxygen, which makes the oxygenhave a partial negative charge, and the hydrogenatoms have a partial positive charge.

Polar or Nonpolar?A polar molecule is one that has a slightly positive end and a slightly negative end.The overall charge of the molecule is NEUTRAL.Example: water

A nonpolar molecule is one where all the electrons are shared equally.Example: O2 (Draw it!)

Binary CompoundsA binary compound is one that is composed of two elements.

CompoundBinaryYes/No?N2H2OO2HClOxidation NumbersAn oxidation number tells you how many electrons an atom has gained, lost, or shared to become stable.

Compounds are NeutralA compound needs the right number of positive ions and the right number of negative ions so the charges balance.Example: Na+Cl-One positive ion and one negative ionneutral compound.Example: How would you balance the compound calcium fluoride?Finding a Common MultipleAluminum OxideAluminum oxidation number: ______Oxygen oxidation number: ______

How can you get this compound to balance???Find a common multiple of each numberin this example the common multiple is: ______. Writing FormulasRules:1. Write the symbol of the element that has the positive oxidation number or charge.2. Write the symbol of the element with the negative oxidation number.3. The charge of one ion becomes the subscript of the other ion. Example:

Lets Do an ExampleLithium Nitride

1. Li1+

2. N?

3. Li1+ N3-

4. Li3NMore Practice1. What is the formula for lead (IV) phosphide?

2. What is the formula for iron (III) oxide?Writing Names1. Write the name of the positive ion.2. Look at table 2, pg. 6163. Write the root name of the negative ion.4. Add the ending ide to the root name.

Writing Names Example:What is the name of the compound CuCl?1. Name of the positive ion in the compound: copper2. See table 2is that element on the table?Yes! Copper I and Copper II, which should we use???3. Write the root name of the negative ion: chlor4. Add the ending ide to the root: 5. Write the entire name:Copper (I) Chloride

Compounds with Complex IonsPolyatomic Ions- a positively or negatively charged, covalently bonded group of atoms.

Example: Baking Soda (NaHCO3)

See Table 4, pg. 619 (and table in your notes!)

Writing Names with Polyatomic IonsYou will need to use table 4, pg. 619!Example: Sr(OH)2

1. Write the name of the positive ionStrontium2. Use table 4, pg 619 to find the name of the negative ion.(OH) is hydroxide3. Put it all together!Strontium Hydroxide

Writing Formulas with Polyatomic IonsWrite the formula for ammonium phosphate(See table 4, pg 619)

1. What is the positive ion? NH4+ (ammonium)2. What is the negative ion?PO43-Balance the charges to make the compound neutral:NH4+ + PO43- = (NH4)3PO4

HydratesA hydrate is a compound that has water chemically attached to its ions and written into its chemical formula. Example: Cobalt chloride hexahydrateIs pink when water is presentTurns blue when it dries.

Naming Binary Covalent CompoundsRemember that covalent compounds are those formed between non-metals. Some pairs of nonmetals can form more than one compound with each other.Example: Nitrogen and Oxygen can form: N2O, NO, NO2, N2O5All these would be nitrogen oxide!

Using PrefixesPrefixes are used to indicate how many atoms of each element are in a binary covalent compound. Example:N2O (dinitrogen oxide)NO (nitrogen oxide) NO2 (nitrogen dioxide)N2O5 (dinitrogen pentaoxide)