Ch.2: Atoms, Molecules, and Ions
Naming
Recall Ionic Bond = electrostatic attraction due to the transfer of vse - s between a metal and nonmetal Covalent Bond = sharing of valence electrons between nonmetals
Naming Rule #1 Identify if it is: 1. Ionic (NaCl) 2. Covalent (CO 2 ) 3. Acidic (HCl)
Examples of Salts (Ionic Compounds) NaCl KBr CaF 2 NaNO 3 Al 2 (CO 3 ) 3
Formulas Atoms gain or lose electrons to form ions Metals lose e - s to form cations Cations have the same name as their parent metal Ex/ Ca 2+ = Calcium
Formulas Atoms gain or lose electrons to form ions Nonmetals gain e - s to form anions Anions end in -ide Ex/ F - = Fluoride
Name the following: 1. Na + 2. Br - 3. Be 2+ 4. Al 3+ 5. S 2-6. O 2-
Naming Ionic Compounds are usually named as metal + nonmetal -ide Ex/CaCl 2 = calcium chloride
What would you name these? 1. NaF 2. KI 3. Rb 2 S 4. MgO 5. Al 2 O 3
Metals with Multiple Charges
Naming Some metals (esp. transition metals) have multiple possible charges. If metals have multiple possible charges, use roman numerals to indicate charge of cation Ex/ Fe 2+ is Iron (II) and Fe 3+ is Iron (III)
Predicting Ionic Charges Group B elements: Many transition elements have more than one possible oxidation state. Note the use of Roman Iron (II) = Fe 2+ numerals to show charges Iron (III) = Fe 3+
Predicting Ionic Charges Some of the post-transition elements also have more than one possible oxidation state. Tin (II) = Sn 2+ Lead (II) = Pb 2+ Tin (IV) = Sn 4+ Lead (IV) = Pb 4+
Predicting Ionic Charges Group B elements: Some transition elements have only one possible oxidation state, such as these three: Silver = Ag 1+ Zinc = Zn 2+ Cadmium = Cd 2+
Exceptions: Some of the transition metals have only one ionic charge, and do not need roman numerals: Silver is always Ag 1+ Cadmium is always Cd 2+ Zinc is always Zn 2+
Figure 2.21 - Common Cations and Anions
What would the names be? 1. KCl 2. HgO 3. MgS 4. CuS 5. SnCl 2 6. FeF 3 7. MnO 2
Acids
Acids Molecules in which one or more H + ions are attached to an anion For simple binary acids: If the anion ends in -ide, the acid is named with the prefix hydro- and the suffix -ic
Acids Ex/ Name the following: 1. HF 2. HCl 3. HI 4. HCN
Polyatomic Ions
Polyatomic Ions Polyatomic Ions = a charged group of atoms that stay together Usually end in ate or ite Acetate: C 2 H 3 O 2 1- Nitrate: NO 3 1- Nitrite: NO 2 1- Permanganate: MnO 4 1- Hydroxide: OH 1- Cyanide: CN 1-
Naming Ex/ NaNO 3 = sodium nitrate
What would the names be? 1. KOH 2. CaCO 3 3. MgSO 4
Note: When writing formulas, you must balance the charge of the polyatomic ion as a whole Use parentheses
Note: Ex/ calcium nitrate
Try One: What would the formula be for sodium sulfate? What about calcium hydroxide?
Oxyanions Assigned special names that must be memorized for naming compounds Oxyanions: Anions that contain an atom of a given element and different numbers of O atoms When there are two members in the series: Name of the member with the smaller number of O atoms ends with -ite Name of the member with the larger number of O atoms ends with -ate
Oxyanions Polyatomic Name Relative # Oxygens Example Hypo ite -2 Hypochlorite ClO - ite -1 Chlorite ClO 2 - ate reference Chlorate ClO 3 - Per ate +1 Perchlorate ClO 4 -
Oxyacids Oxyanions: Anions that contain an atom of a given element and different numbers of O atoms When the anion contains oxygen, based on the name of the anion, the acidic name is formed from the root name of the anion with a suffix of -ic or -ous
Oxyacids
Oxyacids Ex/ Name the following: 1. HNO 3 2. HNO 2 3. H 2 SO 4 4. H 2 SO 2 5. HC 2 H 3 O 2 6. H 3 PO 5
Covalent Bonding
Covalent Bonding Use prefixes to indicate the number of each atom
Prefixes To write the name: prefix + 1 st element + prefix + 2 nd element ide Note: do not use the prefix mono for the first element Ex/ N 2 O = dinitrogen monoxide NO 2 = nitrogen dioxide
1. Cl 2 O 3 Practice by naming these: 2. CBr 4 3. CO 2 4. BaCl 2
State the formulas: 1. diphosphorus pentoxide 2. tetraiodine monoxide 3. sulfur hexafluoride 4. nitrogen trioxide 5. phosphorus trifluoride 6. aluminum chloride
1. Name the following: 1. CuI 2. S 4 N 4 3. NaHCO 3 4. BaCrO 4 2. Give the formulas: Pair-Share-Respond 1. Potassium phosphate 2. Iron (II) oxide 3. Calcium carbonate 4. Sodium sulfide 5. Magnesium perphosphate 56