1. Planner & Brain Teaser Take out your planner Record your test score
Answer this brain teaser:
I am what poor people have and what rich people need. I am what blind people see and what deaf people hear. I am what brave people fear and what kind people hate. And though hateful people have me, only the biggest fools really know me.
What am I?

2. Bonding, Naming & Writing Formulas of Compounds
Ch 5 Structure of Matter
Bonding, Naming & Writing Formulas of Compounds

3. Do You Remember? The difference between a mixture & a compound?
Which one changes properties when made?
Why does it take more energy to separate a compound?
Where is energy stored?

4. Laws of Chemical Combination
1. Law of Definite Proportions – a pure compound has the same elemental composition regardless of its source.
Ex. Table salt (sodium chloride) is salt no matter where or how it was made. It’s always NaCl
2. Law of Multiple Proportions – elements can combine in different ways to form different substances.
Ex. Combine C, H, O in different ways to get different compounds like
C12H22O C6H10O5 -
Sugar
Starch

5. Chemical Formulas
The subscript tells how many atoms of element in front of it.
If outside parentheses, the subscript applies to all inside.
Number 1 isn’t used in formulas; it’s implied.

6. Compounds – chemical combinations
What atoms and how many of each are in the formulas below?
Mg(OH)2 – 1 magnesium, 2 oxygen, 2 hydrogen
CuSO4
Pb(NO2)4
CH4
Al(NO3)3
Mg(OH)2 –
CuSO4
Pb(NO2)4
CH4
Al(NO3)3

7. Molecular VS Empirical Formulas
A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance
An empirical formula shows the simplest
whole-number ratio of the atoms in a substance
H2O
molecular
empirical
H2O
C6H12O6
CH2O O3 O
N2H4
NH2

8. Change Molecular to Empirical
Reduce the subscripts to show lowest whole numbers possible.
C5H10  5 goes into 5 once; 5 goes into 10 twice  CH2
C6H8O6
Hg2F2
CO2
N2O4
C6H14

9. Molecular Mass – determine the mass of the entire molecule
CH4 = 1 12 amu amu = 16amu
H20
NO2
C3H8
CH3OOH
HBr

10. Classes of Compounds Ionic Compound Covalent Compound
Metal (+ ion) attracted to nonmetal (– ion)
Held together by opposite charges (ionic bonds)
Smallest: formula unit
Covalent Compound
Electrons are shared (covalent bonds)
Usually between 2 or more nonmetals
Smallest: molecule

11. Ionic or Covalent? How can you tell?
Look to see if the elements are metal & nonmetal (ionic) or just nonmetal (covalent).
BaCl2 – Barium is metal, Chlorine is nonmetal = Ionic
H2O – Hydrogen is nonmetal, Oxygen is nonmetal = covalent
CaO
Fe2(SO4)3
CO2
NH3
Fr2S

12. Molecular Models

13. Metallic Bonding Metallic bonds occur in metals.
A metal consists of positive ions surrounded by a “sea” of mobile electrons.
Four Characteristics of a Metallic Bond.
Good conductors of heat & electricity
Strong
Malleable and Ductile
Luster

14. High melting & boiling points – stuck together
Network Solids
Which have more attraction between molecules: solids, liquids, or gases?
Covalent Network Solid – covalently bonded atoms linked in one big network or one big macromolecule.
Ionic Network Solid – ion & - ions attracted to each other
High melting & boiling points – stuck together

15. Review
N2 ( )