Polyatomic Ions Lesson 2 Many atoms with a charge. Example (SO4)-2 Blue sheet

O Zn N NO3 NO3 Zn NO3 Zn(NO3)2 Zn -1 -1 -1 +2 +2 +1 -1 +4 IA +2 +3 -4 +4 IA VIIA VIIIA +2 +3 -4 -3 -2 IIA Zinc = +2 IIIA IVA VA VIA

Now called Iron(III) sulfate Fe SO4 -2 SO4 -2 Fe +3 SO4 -2 Fe +3 -2 SO4 Fe2(SO4)3 Fe +3 +1 -1 +4 IA VIIA VIIIA +2 +3 -4 -3 -2 IIA IIIA IVA VA VIA Now called Iron(III) sulfate Iron=+3

Polyatomic Ion Formulas Concept: Polyatomic ions are groups of atoms that behave as one unit. Fact 4: Some ions have more that one atom but their overall charge can be determined. Examples: (SO4) = S +6 and O -8 = -2 (NO3)= N +5 and O -6 = -1 (NH4) = N -3 and H +4 = +1

Polyatomic Ion Formulas Fact 5: These group ions, polyatomic ions, are treated like single ions in formulas, but must have parentheses when more than one is used in a formula. Examples: Ca2+(NO3) 1- ==== Ga3+ (SO4) 2- === (NH4) 1+2O2- ====

Polyatomic Ion Formulas Fact 6: The polyatomic ions are named based on the atoms that they contain. Those with oxygen and another nonmetal are often name "____ate" with the root of the other nonmetal in the blank. Examples: (NO3)1- is ______________ (SO4)2- _______________ (ClO3) 1- _______________

Polyatomic Ion Formulas Fact 7: Those polyatomic ions with one oxygen less than the "ate" ions are named "----ite" ions. Examples: (NO2)1- is nitrite (SO3)2- is ____________ (ClO2)1- is _____________

Examples - Formulas to Names 1. Write the names of the ions 2. Determine the charge of the positive ion I’m a polyatomic ion Ba(ClO4)2 barium perchlorate If the positive ion has a fixed charge, you are finished. Final Name