Writing a formula for an Ionic Compound 1

Writing a formula for an Ionic Compound: 1 st Write the symbols for the ions side by side (cation first): +3 -2 Al O 2 nd Cross over the charges : Al+3 O-2 Al 2 O 3 3 rd Check the subscripts (the smallest possible ratio of ions): Al 2 O 3 Total electrical charge in any compound = 0

Practice: K+1 Br-1 ------ KBr Mg+2 Cl-1 ------ Mg. Cl 2 Na+1 O-2 ------ Na 2 O Mg+2 O-2 ------ Mg 2 O 2 K+1 (NO 3 )-1 ----- KNO 3 Na+1 (SO 4 )- 2 ----- Na 2 SO 4 Pb+2 (NO 3 )-1 ---- Pb (NO 3)2 Al+3 (SO 4 )-2 ----- Al 2(SO 4)3

Writing names of ionic compounds: Write the name of the cation followed by the name of the anion: cation anion Element’s name Monatomic The suffix of the element name change by ide. Chlorine Chloride Oxygen Oxide Polyatomic See reference table (SO 4 ) 2 - -- sulfate. (NO 3 ) 1 - -- nitrate. (NO 2 ) 1 - -- nitrite.

Examples: Mg. Cl 2 Magnesium chloride Na 3 PO 4 Sodium phosphate Ca. O Calcium oxide Ba. SO 4 Barium sulfate

Writing names of ionic compounds: If the cation has more than one oxidation number, you must write it between parenthesis (using roman numeral): Examples: Fe 2 O 3 Iron (III) oxide Cu. Cl Copper (I) chloride

Practice: Write the name of the following: Li. Br ------ Lithium bromide Aluminum fluoride --- Al. F 3 Mg. O ----- Magnesium oxide Ba(OH)2 ------- Barium hydroxide Sodium carbonate ------ Na 2 CO 3 Cu(NO 3)2 ----- Copper (II) nitrate Iron (III) chloride ----- Fe. Cl 3 Ni. SO 4 ----- Nickel (II) sulfate Sodium nitride ----- Na 3 N