Chapter 3

Question 1

Compound

Answer 1

Composed of atoms held together by chemical bonds

Question 2

Ionic Compounds

Answer 2

Consist of POSITIVE and NEGATIVE ions, held together by strong electrostatic attractions. The smallest NEUTRAL unit of an ionic compound is called a formula unit Involve a transfer of one or more electrons from one atom (or group of atoms) to another atom (or group of atoms). EG:

Question 3

Cations

Answer 3

Positively Charged. Typically formed from metals that lose electrons

Question 4

Anions

Answer 4

Negatively Charged. Typically formed from nonmetals that gain electrons

Question 5

Covalent Bonds

Answer 5

Involve Sharing of electrons between two or more NONMETAL atoms

Question 6

Empirical Formula

Answer 6

Gives the RELATIVE number of atoms of each element in a compound. For some compounds, the empirical formula and the molecular formula are identical : e.g H2O EG. Hydrogen peroxide empirical formula-HO, molecular formula= H2O2

Question 7

Molecular Formula

Answer 7

Gives the actual number of atoms of each element in a molecule of a compound. Always a whole number multiple of the empirical formula. EG. Hydrogen peroxide empirical formula-HO, molecular formula= H2O2 For some compounds, the empirical formula and the molecular formula are identical : e.g H2O

Question 8

Atomic Elements

Answer 8

Exist in nature with single atoms as their basic units. Most elements fall into this category

Question 9

Molecular Elements

Answer 9

Two or more atoms of the element bonded together. Do not normally exist in nature with single atoms.

Most molecular elements exist as DIATOMIC molecules (e.g. H2 hydrogen gas, N2, Cl2) - H, N, O,F,CL,BR, I

Polyatomic molecules (e.g. P4 phosphorus, S8 Sulfur) -P4, S8, SE(?)

Question 10

Monatomic Ions of representative elements- METALS

Answer 10

Whenever the metal in this first type of ionic compound forms an ion, the ion always has the same charge (invariable)

Cations

All of group 1A, (1+)

All of group 2A (2+)

Group 3A: ALUMINUM only (Al3+)

Transition metals: Zn2+ (zinc), Sc3+ (Scandium), Ag+ (Silver), Cd2+ (cadmium)

Naming:

1. Binary: Name of cation (metal)+ base name of anion (nonmetal)+IDE

• eg KCl is potassium chloride
• CaO is calcium oxide

Generating forumla: CRISS CROSS RULE

Question 11

Monotomic Ions of representative Elements- NONMETALS

Answer 11

Whenever the metal in this first type of ionic compound forms an ion, the ion always has the same charge (invariable)

Anions

Common monotomic anions

Group 6A= 2- charge

Group 7A= 1- charge

Naming:

• Binary: Name of cation (metal)+ base name of anion (nonmetal)+IDE
  
  • eg KCl is potassium chloride
  • CaO is calcium oxide

Generating forumla: CRISS CROSS RULE

Question 12

Metals that form cations with different charges

Answer 12

Second type of ionic compound contains a metal with a charge that can differ in different compounds. Can form more than one kind of cation. Its charge must be specified for a given compound.

Period 4, Groups 3 through 12 (transition metals)

Group 4A (Sn, Pb)

Group 5A (Bi)

1. Naming:
   
   1. Binary:
      
      1. Name of cation is followed by roman number (in parentheses) that indicaets the charge of the metal in that particular compound
      2. Name of cation+ (charge of cation metal)+ base name of anion (nonmetal)+IDE
         
         1. e.g. CrBr3 = Chromium(III) bromide
      3. Generating forumla: CRISS CROSS RULE

Question 13

Polyatomic ions and Naming

Answer 13

1. Naming
   
   1. Same way as ionic compounds
      
      1. Cation + Polyatomic anion
         
         1. eg. NaNO2 = sodium Nitrite
   2. Oxyions
      
      1. Anions containing oxygen and another element
      2. Series of anions contains different numbers of oxygen atoms and named according to number of oxygen atoms in ion.
         
         1. More O atoms has ATE ending:
            
            1. NO3= Nitrate,
         2. Fewer O atoms has ITE ending
            
            1. NO2= Nitrite
      3. More than two ions in serios,
         
         1. hypo (less than) - ite
         2. per (more than) - ate
2. Generating forumla: CRISS CROSS RULE

Question 14

Hydrates

Answer 14

• Ionic compounds containing a specific number of water molecules associated with each forumla unit
  
  • E.g. Epsom salts is MgSO4*7H2O
    
    • systematic name is magnesium sulfate HEPTAhydrate
    • CoCl2*6H2O is cobalt (II) chloride Hexahydrate
  • Hemi=1/2
  • Mono=1
  • di=2
  • tri=3
  • tetra=4
  • penta=5
  • hexa=6
  • hepta=7
  • octa=8

Question 15

Molecular Compounds: Formulas and Names

Answer 15

Composed of two ore more nonmetals

Write the name of the element with the smallest group number first

If they lie in the same group, write the element with greatest ROW number first

Prefixes given to each element indicate the number of atoms present

Naming: PREFIX + Name of 1st element + prefix + base name of 2nd element + IDE

• Mono=1 If there is only one atom of the first element in the formula, the prefix MONO is normally omitted
• di=2
• tri=3
• tetra=4
• penta=5
• hexa=6
• hepta=7
• octa=8

Question 16

Binary Acids: Formulas and Names