Post on 31-May-2018
8/14/2019 Unit2SectionA Oct 19
1/23
Unit 2 Materials
Structure and UsesSection A: Why We use what we do.
8/14/2019 Unit2SectionA Oct 19
2/23
Intro to Unit 2: Materials:
Structure and Uses Topics introduced include:
Chemical and physical properties
Chemical symbols and formulas The periodic table
Reactivity of metals
Oxidation-reduction
Law of conservation of matter andenergy
Writing and balancing chemical
equations
Use of formulas to calculate molar
8/14/2019 Unit2SectionA Oct 19
3/23
Section A.1
Properties make the difference Every substance has
characteristic properties that
distinguish it form othersubstances
8/14/2019 Unit2SectionA Oct 19
4/23
Section A.1
Properties make the difference Physical properties:
Can be determined without altering the
chemical make up of the material
Color
Density
Odor
Physical changes:
Identity still stays the same
Melting
Boiling
Bending
8/14/2019 Unit2SectionA Oct 19
5/23
Section A.1:
Properties make the difference Chemical properties:
Key to the usefulness of material
(How it will react with other substances) Chemical Change
Transform into new substances
Can be detected in:
The formation of a gas or solid
A color change
Change on the surface of a solid
Temperature change
8/14/2019 Unit2SectionA Oct 19
6/23
A.2 Physical and Chemical
Properties
1. Pure metals have a higher luster (are shiny reflect light)2.The surfaces of some metals become dull when exposed
to air.3. Nitrogen gas, which is a relatively nonreactive element at
room temperature, can form nitrogen oxides at the hightemperature of an operating automobile engines
4. Milk turns sour if left too long at room temperature5. Diamonds are hard enough to be used in drill bits.6. Metals are typically ductile (can be drawn into wire).
7. Bread dough increases in volume if it is allowed to risebefore baking.
8. Argon gas, rather than air is used in many Light bulbs toprevent oxidation of metal filament.
9. Generally, metals are better conductors of heat and
electricity than are non metals.
8/14/2019 Unit2SectionA Oct 19
7/23
1. Pure metals have a higher luster (are shiny reflect light)
Physical
2. The surfaces of some metals become dull when exposed to air.Chemical the metal reacts with oxygen
3. Nitrogen gas, which is a relatively non-reactive element at roomtemperature, can form nitrogen oxides at the high temperature of anoperating automobile engines
Chemical new substances are formed
4. Milk turns sour if left too long at room temperature
Chemical material changes, depends on bacteria in milk5. Diamonds are hard enough to be used in drill bits.
Physical
6. Metals are typically ductile (can be drawn into wire).
Physical
7. Bread dough increases in volume if it is allowed to rise before baking.
Chemical bread rising is due to the production of carbon dioxide8. Argon gas, rather than air is used in many Light bulbs to prevent
oxidation of metal filament.
Chemical Argon does not react with the filament
9. Generally, metals are better conductors of heat and electricity than arenonmetals.
Physical
8/14/2019 Unit2SectionA Oct 19
8/23
Section A.4
The Chemical Elements Elements can be grouped or
classified according to theirsimilarities and differences
Metals, Nonmetals, Metalloids Metals
Iron, tin, zinc, copper
Non-Metals Carbon, Oxygen
Metalloids Silicon, germanium
Relatively few: properties are
intermediate some characteristics ofmetals, some properties of nonmetals,
8/14/2019 Unit2SectionA Oct 19
9/23
Metals, Nonmetals, &
Metalloids1
2
3
4
5
6
7
Metals
Metalloids
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 349
Nonmetals
8/14/2019 Unit2SectionA Oct 19
10/23
Metalsmost elements are
metals
elements to the left ofthe stair step line are
metals or metal likeelements
8/14/2019 Unit2SectionA Oct 19
11/23
Ph ysic a l Pr o p e r t ie so f Me ta ls:
-Luster (shininess)
-Good conductors of heat and
electricity-High density (heavy for their size)
-High melting point
-Ductile (most metals can be drawn out
into thin wires)-Malleable (most metals can behammered into thin sheets)
8/14/2019 Unit2SectionA Oct 19
12/23
Ch e mic a lP roper t i es o fMe ta ls:
-Easily lose electrons
-Corrode easily---Corrosion is agradual wearing away. (Example:
silver tarnishing and iron rusting)
8/14/2019 Unit2SectionA Oct 19
13/23
N o n m e t a l s
-found at the right of the
stair step line
-characteristics are
opposite those of metals
8/14/2019 Unit2SectionA Oct 19
14/23
Ph ysic a l Pr o p e r t ie so f No n me t a ls:
-No luster (dull appearance)
-Poor conductor of heat and electricity-Brittle (breaks easily)
-Not ductile
-Not malleable-Low density
-Low melting point
8/14/2019 Unit2SectionA Oct 19
15/23
Ch e mic a lP roper t i es o fNonmeta l s :
-Tend to gain electrons
8/14/2019 Unit2SectionA Oct 19
16/23
Meta l l o ids
-Elements on both sides of the
zigzag line have properties ofboth metals and nonmetals.
8/14/2019 Unit2SectionA Oct 19
17/23
Ph ysic a l Pr o p e r t ie so f Me ta l lo ids:
-Solids
-Can be shiny or dull
-Ductile
-Malleable
-Conduct heat and electricity
better than nonmetals but not as
well as metals
Semiconductors
8/14/2019 Unit2SectionA Oct 19
18/23
Section A.4:
The Periodic Table 60 elements found by 1800s
Five non metals
2 liquids
The rest all solids
The periodic table
An effort to impose someorganization of the information
related to the elements
Dimitri Mendeleev Russian Chemist produced periodic table
8/14/2019 Unit2SectionA Oct 19
19/23
A little bit of chemistry -
history A little about Dimitri Mendeleev
Family history
Contribution to chemistry
Julius Lothar Meyer
The original periodic table
Henry Mosley
British physicists
Contribution to chemistry
8/14/2019 Unit2SectionA Oct 19
20/23
Section A.4:
The Periodic Table Early Periodic table wasgrouped according to two
main characteristics
Atomic mass
It was known that atoms of
different elements have different
masses.
Combining capacity
How a respective element
combined with other elements.
KCl one to one ratio MgCl one to two ratio
8/14/2019 Unit2SectionA Oct 19
21/23
Section A.10:
The Periodic Table Vertical columns: groups or
families
Similar chemical properties
Horizontal rows: periods
Increasing atomic weights
8/14/2019 Unit2SectionA Oct 19
22/23
A.10 Organization of the
Periodic Table Group 1: Alkali metals (except hydrogen)
Highly reactive
Low densities
Soft enough to be cut with a knife
Group 2 Alkaline: earth metals
Groups 3-12d: transition metals Groups f: transition metals (inner transition
metals)
Group 17-Hologens Group 18: Noble gases Almost entirely un-reactive
Completely filled S and P orbital
Few noble gas compounds can be made
Hydrogen is its own family Other rou s named for first
8/14/2019 Unit2SectionA Oct 19
23/23
Homework
Page 130 #1-5, 7-12, 13-15.