Section 4.2

Naming and Writing Formulas for More Complex Compounds

Period 5Group 6

Confused with

section 4.2?

No need to fear

group 6 is here!

We guarantee that after this power point you will understand section 4.2 a bit more than before you read this lesson.

A. Name of Polyatomic IonsM

em

ori

ze!

A. Imagine Polyatomic Ions!

Hydrogen Phosphate

3-d 2-d

Ammonium

B. Naming Compounds containing Polyatomic Ions

Oxyanions are anions that have different amounts of oxygen atoms

In the oxyanions, the names differ depending on the # of oxygens

-less oxygen: -ite-more oxygen: -ate

Some series consist of more than 2 oxyanions -Least oxygen atoms: hypo

-Most oxygen atoms: per

B. Naming Polyatomic Ions!

Hypochlorite Chlorite

Chlorate Perchlorate

Note* the red spheres are the number of oxygen atoms

C. Introduction to Acids

A polyatomic ion that has H+ ions.

Produce these ions when dissolved in water

Acids have a low pH measure.

Acids usually taste sour.

C. Acids and How to Name Them

Acids That Do Not Contain Oxygen-The prefix hydro- is added in front of the name of the acid.-the suffix –ic is added to the root name of the element

Acids Containing Oxygen-The suffix –ic or –ous is applied to the root name of the element-Use the suffix –ic if the name of the ion ends in –ate.

D. Written Names to Formula

The first step to naming a polyatomic ion from formula is to MEMORIZE and become FAMILIAR with polyatomic ions.

After that, check to see if there are hydrogen or oxygen atoms present

Apply the proper suffixes and prefixes

D. Naming Names to Formula

Remember Higher: -ic ex: sulfuric Lower: ous ex: sulfurous Metals with one valence electron: -ide

ex: hyroxide When there’s more oxygen than the usual

amount: per- ex: peroxide One with less oxygen: -ite ex:nitrite One with more oxygen: -ate ex: nitrate

E. Writing Formulas from Names

Recognize the formulas for the polyatomic ions.

Note the presence of oxygen or hydrogen to see if the compound contains oxyanions or is an acid

Make sure to balance the charge by using subscripts or roman numerals

E. Writing Formulas to Names Part D. applies

here too Mono- doesn’t

apply to the first element

If it doesn’t sound right drop a vowel

1 mono-

2 di-

3 tri-

4 tetra-

5 penta-

6 hexa-

7 hepta-

8 octa-

9 nona-

10 deca-

QUIZ QUIZ QUIZ QUIZ QUIZ

A. Name the Polyatomic Ion

1.H2PO4- 2.DichromateB. Name the polyatomic ion in the compound

1. NH4ClO 2. H202

C. Name the Common Acid1.H3PO4 2.HC2H3O2

Quiz (CONT)

D. Formula Compound to Written Form1.PbO2 2. KOH

E. Written to Formula Compound1. ammonium perchlorate2. dinitrogen pentaoxide

References

http://www.files.chem.vt.edu/RVGS/ACT/notes/Nomenclature.html

http://chemistry.about.com/od/nomenclature/a/nomenclature-ionic-compounds.htm