What is an ion? An ion is an atom (or group of atoms) that has a positive or negative charge

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2 What is an ion? An ion is an atom (or group of atoms) that has a positive or negative charge Cations (+) Formed when an atom LOSES electrons Usually happens to metals in a reaction Anions (-) Formed when an atom GAINS electrons Usually happens to non-metals in a reaction

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4 Monatomic Ions Charged particles made up of only 1 atom Polyatomic Ions Charged particles made up of multiple atoms Symbol Charge (Gained 3 electrons) 1 Sulfur & 4 Oxygen

5 Ionic bonds: Form due to strong attraction between oppositely charged particles Ionic bonds form in large arrays of ions called crystals Ionic compounds can form Binary compounds (2 atoms) or Ternary compounds (more than 2, uses a polyatomic ion) The smallest ratio of ions is called the formula unit. This is what we use for the chemical formula for ionic compounds

6 Binary Compounds 2 Elements Ternary Compounds 2+ Elements

7 Formulas of Ionic Compounds are called Formula Units Lowest whole number ratio of ions or atoms in a compound These represent the ratio of ions in a crystal The ions in a formula must balance to a zero charge! Compounds are NEUTRAL!

8 One Magnesium Two Chlorines

9 Sodium and Chlorine Na has 1 valence electron Cl has 7 valence electrons Both want to be stable Na will give it s one valence electron to Cl so both have a full valence shell This makes Na à Na + and Clà Cl - Because they have opposite charges, they are then attracted to each other and form an ionic bond

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11 Write each ion, cation first Don t show charges in the final formula Overall charge must equal zero If charges cancel, just write symbols If not, use subscripts to balance charges. Do not use a subscript of 1 Use parentheses to show more than one polyatomic ion We will get to Polyatomic Ions in a moment. Or two. Stock system: Roman numerals indicate the ion s charge Use with transition metals and Sn & Pb We will get to this momentarily

12 What is the compound formula for sodium joined with fluorine? Na à Na + F à F - How many of each ion do you need to get a zero charge compound of Na and F? One of each! Compound formula: NaF

13 Mg à Mg 2+ Br à Br - How many of each of these ions do you need? Mg 2+ Br- Br One magnesium ion and two bromine ions MgBr 2

14 Potassium Chloride K + Cl - à KCl Magnesium nitride Mg 2+ N 3- à Mg 3 N 2 Copper (II) chloride Cu 2+ Cl - à CuCl 2

15 Transition metals can form more than one cation with different ionic charges The Stock System of nomenclature uses a Roman numeral to indicate an ion s charge Numeral is placed into parentheses and immediately follows the metal name Example: Fe 2+ à Iron (II) Fe 3+ à Iron (III)

16 Charge Roman Numeral +1 I +2 II +3 III +4 IV +5 V +6 VI +7 VII +8 VIII +9 IX +10 X

17 Copper (II) Chloride, CuCl 2 Means the Copper ion has a 2+ charge The chlorine would still have a 1- charge What would be the charge on Fe for Iron (III) Oxide? 3+

18 To this point we have discussed how to write the ionic formula Now, we must learn how to name the ionic compound based off of the formula

19 We now need to learn how to write the formula names for ionic compounds Naming is termed: Nomenclature Remember: Ionic compounds are made of metals and nonmetal! First: Name the CATION (from the metal) KCl contains potassium à potassium chloride Second: Name the ANION (from the non-metal) ide is added to the end of the anion name KCl à Chlorine becomes chloride

20 Third: IF the cation has more than one charge in nature, the charge must come after the metal in Roman numerals (Stock System) Example: Copper (I) or Copper (II)

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22 Consider the following: Does it contain a polyatomic ion? ide, 2 elements à no ate, ite,3+elements à yes Does is contain a roman numeral? Check the table for metals not in Groups 1, 2, or 13

23 NaBr Sodium bromide AlCl 3 Aluminum Chloride Na 2 CO 3 Sodium carbonate FeCl 3 Iron (III) chloride Mg 3 N 2 Magnesium Nitride K 2 O Potassium Oxide

24 To this point we have discussed monatomic ions One atom creates the negative or positive charge There are ions that are made of multiple atoms, Termed: Polyatomic ions Poly = many The group of atoms in the polyatomic ion creates the overall charge of the polyatomic ion These charges are typically memorized!!!!!

25 We see a lot of these ions in normal, everyday activities Medicine, cleaning products Polyatomic ions are actually covalent compounds inside of ionic compounds!

26 Use parentheses around the polyatomic ion if there are more than one within the compound Ex: (NH 4 ) 2 S The parentheses are around the ammonium ion, NH 4+ The same naming rules apply as they did with binary ionic compounds

27 Lithium Sulfate Li 2 SO 4 Aluminum Acetate Al(C 2 H 3 O 2 ) 3 Copper (II) Chlorate Cu(ClO 3 ) 2 Manganese (IV) Carbonate Mn(CO 3 ) 2 Sodium Permanganate NaMnO 4