# Understanding Formulas Two Classes of Elements What Are Stable Elements? Stabilizing Sodium Stabilizing Oxygen Sodium Loses electrons to Oxygen Oxidation.

## Presentation on theme: "Understanding Formulas Two Classes of Elements What Are Stable Elements? Stabilizing Sodium Stabilizing Oxygen Sodium Loses electrons to Oxygen Oxidation."— Presentation transcript:

Understanding Formulas Two Classes of Elements What Are Stable Elements? Stabilizing Sodium Stabilizing Oxygen Sodium Loses electrons to Oxygen Oxidation Numbers Key Elements Examples

Two Classes of Elements What are the Two Main Classes of Elements? Metals and NonmetalsNoble Elements

What Makes Elements Stable? (Lose e -1 ) (Gain e -1 ) Losing or Gaining e -1. Do metals Lose or Gain e -1 ? Do nonmetals Lose or Gain e -1 ? 0 +1+2+3+4 +5+6+7+8+9 +10-10-9-8-7 -6-5-4-3-2 Oxidation Reduction

Stabilizing Sodium How many e -1 for Na? 11e -1 What is the noble element closest to Na? Ne How many e -1 for Ne? 10e -1 Sodium loses/gains how many electrons? 1e -1 Na  Na +1 + e -1 (protons) + (electrons)=charge (+11)(-10)+1 Oxidation or reduction?

Stabilizing Oxygen How many e -1 for O? 8e -1 What is the noble element closest to O? Ne How many e -1 for Ne? 10e -1 Oxygen loses/gains how many electrons? 2e -1 O + 2e -1  O -2 Oxidation or reduction? (protons) + (electrons)=charge (+8)(-10)-2

Sodium Loses electrons to Oxygen Na  Na +1 + e -1 (Stable Like Neon) Ox or Red? O + 2e -1  O -2 (Stable Like Neon) Ox or Red? How many sodium atoms are needed to satisfy oxygen’s electron hunger? 2e -1 means How many oxygen atoms are needed to satisfy sodium’s electron loss? 2e -1 means Na 2 O two Na one O High Electronegativity Low Electronegativity

Oxidation Numbers All elements Lose or Gain e -1. Some have multiple loss or gain possibilities. Fe +2 Fe +3 S -2 S +4 S +6

Key Elements (99%) H +1 H -1 (99%) O -2 O -1 (Always) Li +1, Na +1, K +1, Rb +1, Cs +1, Fr +1 (Always) Be +2, Mg +2, Ca +2, Ba +2, Sr +2, Ra +2 (Always) Al +3 (with only a metal) F -1, Cl -1, Br -1, I -1 (NO 3 -1 ) ion is always +5 (SO 4 -2 ) ion is always +6

Example One Finding Oxidation Numbers 2(+3)+3(S)=Zero sum of the oxidation #’s = Find Ox #’s for Al 2 S 3 ? zero 2(Al)+3(S)=Zero S = -2 +3 -2

Example Two Finding Oxidation Numbers sum of the oxidation #’s = zero +2 -2 Find Ox #’s for Ca 3 (PO 4 ) 2 ? 3(Ca)+8(O)=Zero +5 2(P)+ 3(+2)+8(-2)=Zero2(P)+ =+5P

Finding Oxidation #’s for Compounds +1-2 +1+5-2 H 3 PO 4 H2OH2O HNO 3 +1+5-2 H 2 SO 4 +1-2 +6 Hg 2 SO 4 +6+1-2 Na 2 Cr 2 O 7 +1 +6 -2 H 2 CO 3 +1 -2 +4 (NH 4 ) 2 CO 3 -3+1+4-2 Ca 3 (AsO 4 ) 2 +2+5 -2 Fe 2 (SO 4 ) 3 +6 +3 -2 Ba(ClO 4 ) 2 +2 +7 -2 Al 2 (CO 3 ) 3 +3+4 -2

Writing and Naming fromulas Naming Formulas Writing Formulas

Naming Inorganic Salts TWO parts to the name 1) Cation 2) Anion Cation Examples Anion Examples Positive Negative Ca +2 Al +3 Fe +2 Na +1 Cl -1 NO 3 -1 SO 4 -2 N -3

Example One Name the formula Fe 2 (CrO 4 ) 3 Step #1 Find The + Ion(s). Iron(II) Fe +2 Iron(III) Fe +3

Example One Step #2 Find The - Ion(s) Chromate CrO 4 -2

Fe 2 (CrO 4 ) 3 Fe +2 Fe +3 CrO 4 -2 Iron(II) Chromate Iron(III) Fe +2 CrO 4 -2 Iron(II) Chromate (+2) (-2) Y+=0 X=1Y=1 Fe CrO 4 X (+2) (-2) 1+=01 Fe +3 CrO 4 -2 Iron(III) Chromate (+3) (-2) Y+=0 X=2Y=3 X (+3) (-2) 3+=02 Fe 2 (CrO 4 ) 3 Example One

Al 2 (CO 3 ) 3 Al +3 CO 3 -2 Carbonate Aluminum Al +3 CO 3 -2 Aluminum Carbonate (+3) (-2) Y+=0 X=2Y=3 X (+3) (-2) 3+=02 Al 2 (CO 3 ) 3 Example Two

Naming a Formula Fe(IO 4 ) 2 Fe(IO 4 ) 3 Iron(III) ( )_( )_ Fe +3 IO 4 -1 31 Iron(II) ( )_( )_ Fe +2 IO 4 -1 21 Name Fe(IO 4 ) 2 Sn(HPO 4 ) 2 SnHPO 4 tin(II) ( )_( )_ Sn +2 HPO 4 -2 2 2 tin(IV) ( )_( )_ Sn +4 HPO 4 -2 42 Name Sn(HPO 4 ) 2 periodate periodate periodate hydrogen phosphate

Sn 3 (BO 3 ) 4 Sn +4 BO 3 -3 Borate Tin(IV) Sn +4 BO 3 -3 Tin(IV) Borate (+4) (-3) Y+=0 X=3Y=4 X (+4) (-3) 4+=03 Naming Example Three Sn 3 (BO 3 ) 4 ( )_( )_ Sn +4 BO 3 -3 43

Writing a Formula From a Name AlPO 3 Na 2 CO 3 Sodium Carbonate ( )_( )_ Na +1 CO 3 -2 12 Aluminum phosphite ( )_( )_ Al +3 PO 3 -3 33 Ca 3 (AsO 4 ) 2 Calcium Arsenate ( )_( )_ Ca +2 AsO 4 -3 2 3

Writing a Formula From a Name H 3 PO 4 LiNO 3 Lithium Nitrate ( )_( )_ Li +1 NO 3 -1 11 Hydrogen Phosphate ( )_( )_ H +1 PO 4 -3 13 Ca 3 (AsO 4 ) 2 (NH 4 ) 2 CO 3 Ammonium carbonate ( )_( )_ NH 4 +1 CO 3 -2 1 2 Calcium Arsenate ( )_( )_ Ca +2 AsO 4 -3 2 3 Hg 2 SO 4 Fe(IO 4 ) 3 Iron(III) periodate ( )_( )_ Fe +3 IO 4 -1 31 Mercury(I) Sulfate ( )_( )_ Hg 2 +2 SO 4 -2 22 Na 2 Cr 2 O 7 Ba(ClO 4 ) 2 Barium Perchlorate ( )_( )_ Ba +2 ClO 4 -1 2 1 Sodium Dichromate ( )_( )_ Na +1 Cr 2 O 7 -2 1 2 Pb(SO 4 ) 2 Lead(IV) Sulfate ( )_( )_ Pb +4 SO 4 -2 4 2 (Cation +? ) X (Anion -? ) Y (+?) (-?) Y+=0X Lowest Whole Number Ratio If X or Y is 2 or greater... and the ion is polyatomic. Ba +2 Cr 2 O 7 -2 Hg 2 +2 Pb +4

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