History

Greeks: Matter is made of_________________________

Plato, Aristotle: Matter is___________________________

Democritus: Matter consists of _______________________________

Theories not tested experimentally no scientific progress made.

Alchemy: sulfur, mercury, antimony discovered. Lab techniques such as ___________ developed, but ____________________

Robert Boyle: First chemist to carry out ________________experiments. Defined element as substance which could not be broken down into further substances.

Lavoisier: Law of conservation of mass:

Proust: Law of Definite Proportions:

John Dalton: Atomic Theory (1808)

Law of Multiple Proportions:

When two elements form a series of compounds, the masses of the second element that combine with a fixed mass of the first element can be reduced to ______________________

carbon-oxygen wgt oxygen

compound that combines with 1 g C

cpd 1 1.33 g

cpd 2 2.66 g

1:2 ratio for g oxygen

Assumptions of Dalton's Theory:

1. Each element is made up of tiny particles called atoms.

2. All atoms of a particular element are _____________

3. Atoms cannot be ___________________________________________________

4. Atoms of different elements__________________________________________________________

5. A chemical reaction consists ___________________________________________________

Dalton's theory was useful because it explained:

a)

b)

c)

CO 12 g C 16 g O

CO2 12 g C 32 g O

How can we determine chemical formulas?

1 g H + 8 g O -> 9 g water

HO ? (Dalton) H2O ? HO2 ?

Gay-Lussac: Law of Combining Volumes: For chemical rxns involving gases, combinations occur in simple proportions by ____________.

Experimentally:

H + O water

2 : 1 2

Avogadro's Hypothesis:

Formation of water

Case 1 H + O -> HO

1 : 1 : 1

Case 2 H + 2 O -> HO₂

1 : 2 : 1

Case 3 2 H + O -> H₂O

2 : 1 : 1

Case 4 2 H₂ + O₂ -> 2 H₂O

2 : 1 : 2

rel. mass of H = 1 2×1 = 2

rel. mass of O = 16 1×16 = 16

mass H : mass O is 1 : 8

The Periodic Table

Chemist's tools for organizing chemical knowledge:

1. Periodic Table

2. Models of Chemical Bonding

Mendeleev (1872)

Periodic Law:

family or group: a column in the periodic table containing elements with similar _______________.

E.g., 1 A, alkali metals: very reactive, form M+ ions in compounds

Metals

Properties:

generally solid (exception Hg)

good conductors of heat and electricity

metallic luster

ductile and malleable

1A alkali metals

2A alkaline earth met.

transition metals

Melting Pt. within a group:

W > Mo > Cr (4B - 8B)

Li > Na > K 1A

Reactivity of Metals

1. Active metals

Li,Na,K,Rb,Cs,Ca,Sr,& Ba react with water:

2. Intermediate metals Cr,Mn,Fe,Co,Ni,Zn do not react with water, but do react with dilute acid:

3. Noble metals

Cu,Ag,Au,Pt,Rh,Ir,Hg do not react with most acids,e.g., HCl

Nonmetals

gases: O₂,N₂,F₂,Cl₂

liquid: Br₂

solid: B,C,Si,S,Se,I₂ tend to be brittle

P₄ waxy

poor electrical conductors

(graphite is a conductor; Si is a semiconductor)

7A halogens (salt-formers)

reactivity:

MP/BP: