Chapter 6 – Chemical Names & Formulas

1. Chapter 6 – Chemical Names & Formulas 6.1 Introduction to Chemical Bonding 6.2 Representing Chemical Compounds 6.3 Ionic Charges 6.4 Ionic Compounds 6.5 Molecular Compounds & Acids 6.6 Summary of Naming and Formula Writing

2. 6.1 Introduction to Chemical Bonding • Molecules and Molecular Compounds • Molecule: the smallest electrically neutral part of a substance that has all of the same properties of that substance. • Molecules can be a variety of combinations of elements that may combine chemically to form molecular compounds. • As a general rule, molecules are usually two or more non-metallic elements joined together. • e.g., CO2 , C2H6O, ….

3. 6.1 Introduction to Chemical Bonding (cont.) • Ions and Ionic Compounds • Not all compounds are molecular, many are ionic. • Ions are atoms or groups of atoms that are electrically charged. • Ionic compounds are generally formed from a metal and a non-metal.

4. 6.1 Introduction to Chemical Bonding (cont.) • Ions and Ionic Compounds (cont.) • Ions can be either positive (cations) or negative (anions) • Cations go by the name of the element (Na+ becomes “sodium ion”) and with anions, the ending of the name changes to “-ide” (Cl1- becomes “chloride”). • As a general rule, anions form from non-metals and cations form from metals. • Use the periodic table for location and tendency of ion formation and/or an ion table. • Be able to compare and contrast similarities and differences between molecular and ionic compounds: Table 6.1 lists a few.

5. 6.2 Representing Chemical Compounds • Chemical Formulas • “The kind and number of atoms in the smallest representative unit of the substance.” • Can be either a molecular formula (for molecules) or a formula unit (for ionic compounds)

6. 6.2 Representing Chemical Compounds (cont.) • Laws of Definite and Multiple Proportions • In the simplest terms, masses of elements are always in the same proportions when combining into compounds and in ratios of small whole numbers (Dalton).

7. 6.3 Ionic Charges • Monatomic Ions • Ions that consist of only 1 atom. • e.g. chloride – Cl-, hydrogen – H+, iodide – I- • Polyatomic Ions • Ions that are tightly bound groups consisting of two or more atoms, behave as a unit, and carry a charge. • e.g. acetate – C2H3O2-, ammonium – NH4+ • Use periodic table & Tables 6.2, 6.3, & 6.4

8. Chapter 6 Assignment • CPQs # 1 pg. 166 # 45-49, 51-54

9. 6.4 Ionic Compounds • Writing Formulas and Names for Ionic Compounds • Binary: compounds composed of two element ions. • e.g. BaCl2, NaCl, HCl, Fe2O3 • Some rules to consider: • Cations get written first • Net charge on compound must be zero • Criss-cross! Shoelace? • Naming Ionic Compounds • Work things in reverse! - Ternary Ionic Compounds • Same as before except you are using polyatomicanions! • e.g. Ca(NO3)2, Li2CO3, Mg(OH)2 • DO NOT ATTEMPT TO SPLIT UP POLYATOMIC ANIONS!

10. 6.5 Molecular Compounds & Acids • Molecular Compounds • Easy to recognize: two non-metals! • Ending and prefixes are important here… • Table 6.5 • e.g. N2O, CO2, SF6 • Naming Common Acids • Memorize the list on page 160!

11. Chapter 6 Assignment • CPQs # 1 pg. 166 # 45-49, 51-54 • CPQ’s #2 pp. 166-167 • #57,58,61,62,64,66