Unit 2- Materials: Structure and Uses Section 2. A – Why we use what we do.
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Transcript of Unit 2- Materials: Structure and Uses Section 2. A – Why we use what we do.
Objectives 1. SWBAT define properties and changes. 2. SWBAT distinguish between physical
and chemical changes and classify examples of each.
3. SWBAT differentiate between metals, non metals, and metalloids and their locations on the period table.
Wkst – U2A1, HW pg 130 (1-6)
2.A.1 Properties make the difference What are some materials people of the past
have used as currency? What makes a material suitable or useable
to produce coins? How important is appearance or cost?
Physical Properties Characteristics that distinguish elements
from other things Ex. Color, density, odor… Can be observed without altering chemical
structure
Chemical vs. Physical Changes
Chemical Change Physical Change
-substance changes into one or more NEW substances
EX-
-Appearance can change although chemical structure remains intact
EX-
Example 1 Iron RUSTING:
Observing a chemical change can often mean the formation of a gas or solid
Thermal energy can be given off or absorbed
p.111- Developing Skills Consider the statement: Copper
compounds are often blue in color. Does this statement describe a physical or chemical property? Why?
p. 111 – Developing Skills Consider this statement: Oxygen gas
supports the burning of wood. Does this statement refer to the physical or chemical property of oxygen gas? Explain.
Answer Burning or combustion of wood- involves a
chemical reaction Wood and oxygen (reactants) change into
ash, carbon dioxide and water vapor.
Objectives 1. SWBAT distinguish between physical
and chemical changes and classify examples of each.
A.3 Properties Matter: Designing the Penny 1. Cost
A. Cost of the production of the penny must be matched by it’s face value ($0.01)
B. Early 1980s Copper became too expensive and Zinc replaced it
C. In 1943, during WWII, Zinc plated steel pennies (quickly corroded)
A.3 Properties Matter: Designing the Penny 2. Solution
Post 1982 pennies – 97.5% Zinc Copper coating a Zinc Core
A.4. Chemical Elements Elements are classified in three major
groups: Metals Nonmetals Metalloids
Take out your PTOE to color in the different sections
Physical Properties of Metals Malleability Ductility Luster Heat conductors and
electrical conductors Typically reacts with
acids Ex. Iron (Fe), tin (Sn),
zinc (Zn), and copper (Cu)
Properties of Nonmetals
Dull in appearance Brittle Do not conduct electricity Ex. Carbon (C) and Oxygen (O)
Do Now List the following as a chemical or physical
change 1. A piece of wood burns to form ash. 2. Water evaporates into steam. 3. A piece of cork is cut in half. 4. A bicycle chain rusts. 5. Food is digested in the stomach. 6. Water is absorbed by a paper towel. 7. A change in color
Objectives 1. SWBAT review physical and chemical
changes 2. SWBAT identify trends in the periodic
table.
Objectives SWBAT identify properties of metals,
nonmetals, or metalloids SWBAT create their own trends in the
periodic table.
Dimitri Mendeleev Created a periodic table of elements based
on: 1. Atomic Weights 2. “Combining Capacity”
Now you Try Turn to page 119 and follow steps #1-6 Try to create your own periodic table based
on several different properties
Trends in Periodic Families
Alkali Metal Family: Group 1 Highly reactive Metals (cations)
Noble Gas Family: Group 18 Unreactive (chemically inert) elements
Halogen Family: Group 17 Highly reactive (anions)