Bonding Part 2
Chemical Formulas Chemical formulas a group of chemical symbols and numbers that represent the number of atoms of each element that make up a compound. ( H O) 2 In a chemical formula, the element with the positive charge is always written first.
Subscripts Subscript the number that shows how many atoms of an element are in the compound. Examples H 0, CO 2 2 The number 2 is the subscript in each.
Valence Numbers Valence number The number of electrons an atom needs to gain, lose, or share to become stable. (Gain electrons negative valence) (Lose electrons positive valence.)
Binary Compound a compound composed of ONLY 2 elements. Polyatomic Ion- a group of positively or negatively charged covalently bonded atoms.
How to Write Formulas 1. Write the symbol correctly for both elements. 2. Write the valence number above each symbol. Make sure you have a positive first, and then a negative. 3. Criss-cross valences to make a subscript. 4. NEVER write 1 as a subscript. (It is understood to be 1 if there is no number.) 5. Reduce to lowest terms.
Examples Sodium Chloride Aluminum Oxide Copper (I) Sulfide Iron (III) Iodide
Practice Problems Aluminum Bromide Magnesium Nitride Calcium Iodide Potassium Sulfide Copper (I) Chloride Barium Fluoride Hydrogen Oxide Lead Bromide
Check your Work Aluminum Bromide Magnesium Nitride AlBr 3 Mg 3 N 2 Calcium Iodide Potassium Sulfide CaI 2 K 2 S Copper (I) Chloride Barium Fluoride CuCl Ba F 2 Hydrogen Oxide Lead Bromide H 2 O PbBr 2
Practice Problems 1. Lead Iodide 2. Barium Fluoride 3. Tin (II) Nitride 4. Lithium Chloride 5. Sodium Bromide 6. Iron (II) Oxide
7. Potassium Fluoride 8. Silver Bromide 9. Calcium Chloride 10. Copper (I) Iodide 11. Aluminum Nitride 12. Cobalt (II) Sulfide
Calcium Phosphate Tin (IV) Chromate Ammonium Oxide Magnesium Sulfate
Naming Compounds 1. Change the ending of the second element to ide. (Do not change the names of polyatomic ions.) 2. Check to see if Roman numeral is needed. Ex: NaCl - Sodium Chloride Fe O Iron (III) Oxide 2 3
Practice Problems 1. PbI 2 2. BaF 2 3. Sn 3 N 2 4. LiCl 5. NaBr 6. FeO 7. KF 8. AgBr 9. CaCl 2 10. CuI 11. AlN 12. CoS
Homework Check 1. K 2 O 6. Ca 3 (PO 4 ) 2 2. NaC 2 H 3 O 2 7. FeBr 2 3. Ag 2 SO 4 8. HClO 3 4. ZnCO 3 9. MgSO 3 5. CrS 10. (NH 4 ) 3 PO 4
Homework Check Cd CrO 4 Cu(ClO 3 ) 2 Al 2 O 3 PbC 2 O 4 FePO 4 KClO 3 AgNO 3 SnS 2 NaClO 2 SbCl 5 ZnI 2 Li 3 PO 4
Predicting Reactions between Elements To form an ionic bond, a metal bonds to a non-metal. Metals to the left of stair-step line except H. Non-metals to the right of stair-step line, except H Metalloids along stair-step except Al which is a metal.
Properties of compounds. See handout and p. 288 in textbook.
Naming Compounds Examples Zn 3 N 2 K 2 SO 3 CuO Ba(C 2 H 3 O 2 ) 2
Homework check 1.Iron (ll) Hydroxide 2. Aluminum Perchlorate 3. Chromium (ll) Acetate 4. Tin (lv) Chloride 5. Lead Chromate 6. Copper (ll) Sulfide 7. Potassium Hypochlorite 8. Mercury (ll) Dichromate 9. Calcium Hydroxide 10. Tin (ll) Sulfite
Homework check 11. Zinc Phosphate 12. Barium Fluoride 13. Sodium Nitrate 14. Cadmium Carbonate 15. Mercury (ll) Peroxide 16. Iron (lll) Sulfite 17. Antimony (V) Oxide 18. Copper(l) Permanganate 19. Chromium (lll) Oxalate 20. Ammonium Sulfate
Homework check Chlorine - nonmetal Boron - metalloid Zinc - metal Neon - nonmetal Sodium - metal Silver - metal Silicon - metalloid Helium - nonmetal Bromine - nonmetal Francium - metal Aluminum - metal Calcium - metal Hydrogen - nonmetal Nickel - metal Magnesium - metal Fluorine - nonmetal Potassium - metal Uranium - metal Carbon - nonmetal Argon - nonmetal
1.Ammonium Phosphate 11. Manganese(ll) Oxide 2. Iron (ll) Bromide 12. Tin (lv) Iodide 3. Hydrogen Chlorate 13. Calcium Oxide 4. Sodium Acetate 14. Potassium Chloride 5. Silver Sulfate 15. Copper (l) Hydroxide 6. Chromium (lll) Sulfide 16. Ammonium Sulfide 7. Potassium Oxide 17. Aluminum Carbonate 8. Tin (ll) Oxide 18. Hydrogen Sulfite 9. Copper (ll) Phosphate 19. Iron (lll) Sulfate 10. Zinc Sulfate 20. Aluminum Nitride