Chapter 5 Section 1
Chemical Bonds- the attractive force that holds atoms or ions together
Compound: a substance made up of atoms of 2 or more different elements joined by chemical bonds
· A compound always has the same chemical formula. EX: H2O is WATER and always water.
· Some compounds are made of molecules.
· Strength of attraction between molecules can vary.
· Attractions between water molecules are called H-bonds
· Have a formula
Mixture: a combination of 2 or more substances that are not chemically combined
· Does not have a formula
Chapter 5 Section 2
Ionic and Covalent Bonding
1. Ionic bonds:
o They give their electrons (valence) away
o Metal (blue) + anything
o Conduct electricity
o Metallic bonds: electrons move freely
2. Covalent bonds:
· Share their valence electrons
· Nonmetal (yellow) + nonmetal
· Don’t always share equally
3. Polyatomic Ions: (chart 158)
· made of 2 or more atoms
· examples: OH- or NH3+ or CO32- or CH3COO-
· parentheses are used on poly’s
· -ite or –ate (tells O2 content)
Bonded atoms have a stable configuration:
· 8 valence electrons (like noble gasses)
· 2 valence electrons for H and He
Chapter 5 Section 3
Naming Compounds:
Cations:
· ions with a positive charge
· metals
· transition metals are multi-
· lanthanides and actinides are multi-
Anions:
· ions with a negative charge
· nonmetals
HOW TO NAME from a Formula:
· Name cation first its real name
· Cations are always written first
· Name anion second it’s real name
· Anions are always written second
· Change the anion ending to –ide
· Use prefixes to indicate the number of each atom
· Prefixes go out front of the element they are attached to
· Cations cannot get mono-
· NO double letters
· Polys keep their real names no matter if a cation or an anion
EXAMPLE: CCl4
· Carbon tetra Chlorine
· Carbon tetra chloride
ANOTHER EXAMPLE: LiOH
· Lithium Hydroxide
ANOTHER EXAMPLE: H2CO3
· Dihydrogen Carbonate or Carbonic Acid
HOW TO WRITE FORMULAS FROM NAME:
· Find the charge on your cation
· Find the charge on your anion
· Find the symbol of your cation
· Find the symbol of your anion
o -ide indicates an element off the periodic table
o -ite and –ate indicates the polyatomic ions
· CRISS-CROSS the charge
· Do NOT write 1
· On multivalents (more than one charge) the parentheses tells what charge to use
· Reduce subscripts on anything but a poly (POLY subscripts CANNOT be reduced)
· Use parentheses to protect polys if the crissed charge is greater than 1
PG 161 examples
a. Lithium oxide Li+1 O-2 Li2O
b. Beryllium chloride Be+2Cl-1 BeCl2
c. Titanium (III) nitride Ti+3N-3 Ti3N3 TiN
d. Cobalt (III) hydroxide Co+3OH-1 Co(OH)3
Section 3 Review: Answers
1. a. iron (II) oxide b. manganese (III) ferride c. chromium (II) chloride d. copper (II) sulfide
2. a. diarsenic pentaoxide b. silicone tetraiodide c. tetraphosphorus trisulfide d. tetraphosphorus decaoxide
e. selenium dioxide f. phosphorus trichloride
3. To indicate the charge to be used on multivalent elements
4. 6
7. a. Mg2SO3 b. RbBr c. CrF2 d. Ni2CO3
Chapter 5 Section 4:
Organic Compounds:
· contains carbon atoms
· covalently bonded
· does not include carbonates and oxides
Inorganic Compounds:
· does not contain carbon atoms
Alcohols:
· end in –OH