1 1. Define electronegativity. a measure of the ability of an atom in a chemical compound to attract electrons. 2. On the periodic table, where are the LEAST/MOST electronegative elements found? Least-Bottom left Most-Top right What are the rules for writing and naming stable ionic formulas?
2 Chemical Bonding Vocabulary (Ch. 7 & 8) 1. Chemical formula 2. Ionic bonds 3. Ionic compounds 4. Metallic bonds 5. Octet rule 6. Valence electrons 7. Covalent bond 8. Diatomic molecule 9. Double covalent bond 10.Hydrogen bond 11.Molecular formula 12.Polar bond 13.Polyatomic ion 14.Single covalent bond 15.Triple covalent bond Word Definition My Own Words Pic. Or Ex.
CHEMICAL BONDING 3
4 Chemical Compounds Atoms of elements are not chemically stable until they have 8 valence electrons (octet rule). Atoms gain, lose, or share electrons with other atoms to become chemically stable (8 valence electrons) The action taken by the electrons determine the type of bond formed Transferred ionic bond Shared covalent bond
Introduction to Chemical Bonds 5 TWO basic forms of bonding: Ionic transfer of 1 or more electrons from one atom to another (one loses, the other gains) forming oppositely charged ions that attract one another Covalent some valence electrons shared between atoms Most bonds are somewhere in between ionic and covalent.
The type of bond can usually be calculated by 6 finding the difference in electronegativity of the two atoms that are going together.
Electronegativity Difference If the difference in electronegativities is between: 1.7 to 4.0: Ionic 0.0 to 1.7: Covalent 7 Example: NaCl Na = 0.9, Cl = 3.0 Difference is 2.1, so this is an ionic bond!
Ionic Compounds Ionic bonds form from the attractions between oppositely charged ions. Metal + Nonmetal Metals tend to lose electrons to become positively charged (cations) Nonmetals tend to gain electrons to become negatively charged (anions)
QR Code Activity-Example K F Dot Diagrams (show valence electrons)
QR Code Activity-Example K + F _ The ionic bond is the attraction between the positive K + ion and the negative F - ion
QR Code Activity-Example KF Put the symbols together and you have the chemical formula
Naming Ionic Compounds For the first element, use the full element name Potassium For the second element, change the ending to -ide Fluoride KF Potassium Fluoride
LABEL YOUR PERIODIC TABLE:
Determine the chemical formulas by balancing the charges. Bonding pair Cation Anion Balance Charges Formula Name Sodium and Chlorine Calcium and Fluorine Aluminum and Oxygen
Special Ions Transition Metals Can have more than one charge Ex: Cu + and Cu 2+ Ex: Fe 2+ and Fe 3+ Use a Roman Numeral in the name to show the CHARGE copper(i) and copper(ii) iron(ii) and iron(iii)
Transition metals Use a roman numeral to indicate the charge of the metal for all metals other than Groups 1 & 2 and Aluminum. Example: Copper & Oxygen Cu +1 O Cu +2 O Cu +3 O
QR Codes!
Chemistry CAT Joke
1. What is the name for NaCl? A. sodium chloride B. sodium chlorine C. sodium I chloride
2. What is the correct formula for iron (III) chloride? A. FeCl B. Fe 3 Cl C. FeCl 3
3. What is the correct formula for Al +3 and Cl -1? A. Cl 3 Al B. AlCl C. AlCl 3
4. What is the name for CaF 2? A. calcium fluoride B. calcium II fluorine C. calcium II fluoride
5. What is the correct formula for compound formed when a sodium ion combines with a fluoride ion? A. NaF 2 B. NaF C. Na 2 F
6. What is the correct formula for copper (II) chloride? A. CuCl B. Cu 2 Cl C. CuCl 2
7. What is the correct formula for calcium oxide? A. CaO 2 B. CaO C. Ca 2 O
8. What is the name for MgS? A. magnesium II sulfide B. magnesium sulfur C. magnesium sulfide
9. What is the correct formula for silver (I) chloride? A. SiCl B. AgCl C. AgCl 3
10. What is the formula formed by a potassium ion and a sulfur ion? A. K 2 S B. KS C. KS 2
11. What is the compound formed from Ca +2 and F -1? A. calcium fluoride B. calcium II fluorine C. calcium II fluoride
12. What is the formula formed by Li +1 and O -2? A. Li 2 O B. LiO C. LiO 2
Bell Ringer: 1. Define electronegativity. a measure of the ability of an atom in a chemical compound to attract electrons. 2. On the periodic table, where are the LEAST/MOST electronegative elements found? Least-Bottom left Most-Top right EQ: What are the rules for writing and naming stable ionic formulas? The positive and negative charges must be balanced. Change the ending of the nonmetal s name to -ide.
1. What is an ion? An atom that has gained or lost electrons 2. Why do atoms become ions? To become more stable (by having a full outer energy level).
Compounds Yes It s Ionic! Is the first element a metal? No, the first element is not a metal. Is H is the positive ion? No Metals: Group I or II, B or Al Metals: Transition and all others Polyatomic ions Acidic Compound Covalent Compound
Special Ions-Polyatomic A tightly bound group of atoms that act as a unit but have a charge Examples: (OH - ) hydroxide ion Ca (SO 4 2- ) sulfate ion Na (SO 3 2- ) sulfite ion Al (NH 4+ ) ammonium ion O
Quick Tips: Shortcuts to Chemical Formulas Oxidation Number: Shows the charge of an ion Mg 2+ Write the oxidation numbers across the top of your periodic table
Quick Tips: Shortcuts to Chemical Formulas 1+ 2+ 3+ 4+/- 3-2- 1-
Quick Tips: A Shortcuts to Chemical Formulas 1. Use the periodic table to determine the oxidation number (charge) for each ion involved. 2. Criss-cross the oxidation numbers to become the subscripts. 3. Reduce if necessary. Li 1+ O 2- Li 2 O Lithium oxide
Use your reference sheet to write the correct formula for ammonium sulfate. (NH 4 ) 2 SO 4 How do you name ionic formulas with: -transition metals -polyatomic ions Use a roman numeral to indicate the charge of the metal Use the polyatomic name without any changes
Use your reference sheet to write the correct formula for Copper II Nitrate. Cu(NO 3 ) 2 The objective for any ionic compound is to have a net charge of. Zero The positive and negative charges should cancel out.
Review Make a compound with the following ions Li +1 and O -2 NH +1 4 and S -2 Zn +2 and SO -2 4
Review Write the formula for the following compounds Barium nitrite Potassium oxide Iron (III) sulfide
Review Write the name for the following compounds CaCl 2 Cr 2 S 3 Al 2 (CrO 4 ) 3