Science joke of the day!!! Question: What do you call a king’s fart? Answer: A noble gas!

Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Word breakdown!!! “poly” means many and “atomic” refers to atoms  polyatomic ions = an ion that is a GROUP of many atoms

Polyatomic Ions A polyatomic ion is a group of atoms atoms are connected by covalent bonds (sharing of electrons) has an overall ionic charge (positive or negative charge) can’t exist on its own Look at the list of polyatomic ions on the back of your periodic table or on pg. 92 of your textbook.

Some Compounds with Polyatomic Ions Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

Polyatomic ions are an important part of many materials:

Writing formulas for polyatomic ions Rules for writing the formula of a compound with polyatomic ions: Identify each ion and its charge Use “swap & drop” method to find subscripts Brackets must be used around the polyatomic ion when writing the subscript (except when the subscript is a “1”)

Write the formula for Cu+2 and NO3-1 You would write it like this: Cu(NO3)2 The 2 tells us we need 2 of the NO3-1 ions. 1 Cu atom 2 N atoms 6 O atoms

Naming Compounds with Polyatomic Ions The positive ion is named first followed by the name of the polyatomic ion. NaNO3 sodium nitrate K2SO4 potassium sulfate Fe(HCO3)3 iron(III) bicarbonate or iron(III) hydrogen carbonate (NH4)3PO3 ammonium phosphite ***Do not change the ending to “-ide” when dealing with polyatomic ions!!***

Learning Check Select the correct formula for each: A. aluminum nitrate 1) AlNO3 2) Al(NO)3 3) Al(NO3)3 B. copper(II) nitrate 1) CuNO3 2) Cu(NO3)2 3) Cu2(NO3) C. iron (III) hydroxide 1) FeOH 2) Fe3OH 3) Fe(OH)3 D. tin(IV) hydroxide 1) Sn(OH)4 2) Sn(OH)2 3) Sn4(OH)

Solution Select the correct formula for each: A. aluminum nitrate 3) Al(NO3)3 B. copper(II) nitrate 2) Cu(NO3)2 C. iron(III) hydroxide 3) Fe(OH)3 D. tin(IV) hydroxide 1) Sn(OH)4

Learning Check Name each of the following compounds: A. Mg(NO3)2 B. Cu(ClO3)2 C. PbO2 D. Fe2(SO4)3 E. Ba3(PO3)2

Solution Name each of the following compounds: A. Mg(NO3)2 magnesium nitrate B. Cu(ClO3)2 copper(II) chlorate C. PbO2 lead (IV) oxide D. Fe2(SO4)3 iron(III) sulfate E. Ba3(PO3)2 barium phosphite

Homework Workbook page 48 + 49 Next class will be a review of Chapter 3.1 and 3.2 Ch 3.1 + 3.2 test  DURING LONG BLOCK