Physical Defences against Pathogens
Chapter 2 – Common Reactions in Our Lives
Science 14
Name: _______________________________________
Date: ________________________________________
Pure substances: Elements and Compounds
What are elements?
• Elements are substances that __________________ be broken down into other substances
• Dmitri Mendeleev organized the elements from lightest to heaviest and created the __________________ table.
• The lightest elements are on the left side and the heaviest elements are on the right side
[pic]
The Periodic Table
• Each square of the periodic table gives us ________________________ about a particular element
[pic]
Patterns & Trends
• __________________: horizontal row on the periodic table
o There are 7 periods in total
• __________________ or family: vertical column on the periodic table
o There are 18 groups in total
o Elements in a group have similar properties or characteristics (they behave in a similar manner)
Group 1: Alkali Metals
• Li, Na, K, Rb, Cs
• Most __________________ metals (especially with water)
• Never found in pure form in nature
Group 2: Alkaline Earth Metals (Mg, Ca, Ba)
o Very reactive
Group 7: Halogens (F, Cl, Br, I)
o Most reactive non-metals
o Diatomic elements (2 atoms together)
Group 8: Noble Gases(Mg, Ca, Ba)
o The royalty of the periodic table – they’re too good to associate with anyone else
o Most non-reactive elements
Atoms
• All elements in the periodic table are made up of _________________
• Atoms are the smallest possible bits of matter
o Ex: Water (H2O) is made up of 2 hydrogen atoms and 1 oxygen atom
Properties of Elements
• Metals:
o Ductile (can be stretched into wire)
o Shiny
o Conductors of electricity
o Malleable
• Non-metals
o Not ductile
o Dull
o Poor conductors of electricity
• Metalloids
o Metalloids are found along the “staircase line” of the periodic table
o Metalloids have properties that are a mix of metals and non-metals
Assignment:
← On your blank periodic table, colour:
o The alkali metals blue
o The alkaline earth metals red
o The halogens yellow
o The noble gases green
o The metalloids purple
Examples:
1. Which element is located in group 1 and period 1?
___________________________________________
2. Which element is located in group 2 and period 4?
___________________________________________
3. Which element is located in group 17 and period 3?
__________________________________________
The Elements:
- Sometimes you will see little “s”, “l” or “g” beside each of the elements. What do you think this means?
o H2O(g), H2O(l), H2O(s)
__________________________________________________________________________________________________________________________________________________________________________________________________________________
Metals and Non-Metals
Classify Each of the following as a metal or a non metal:
a) Greenish yellow gas
b) Silver-colored solid that conducts electricity
c) Greyish solid that is shiny when sanded
d) Very brittle brown crystal
e) Very shiny silver-colored liquid that conducts electricity
Elements and Compounds:
What is the symbol for each of the following elements?
Nitrogen __________________________
Iron ______________________________
Carbon ___________________________
Oxygen ___________________________
Helium ___________________________
Potassium ________________________
Chemical Formulas:
H2O ( How many atoms of Hydrogen does water have? How do we know?
H2O
Examples:
|Compound Name |Common Use |Chemical Formula |Number and Name of Elements |Total number of Atoms |
|Calcium Carbonate |Chalkboard Chalk |CaCO3 | | |
|Sodium Phosphate |Heavy-duty Cleaner |Na3PO4 | | |
|Magnesium Chloride |De-icing Roads |MgCl2 | | |
|Hydrogen Peroxide |Disinfectant |H2O2 | | |
|Glucose |Sugar |C6H12O6 | | |
|Carbon Dioxide |Fizz in pop, dry ice |CO2 | | |
Evidence of Chemical Change:
1. A different colour is produced
2. An odour can be detected
3. Bubbles appear
4. A solid forms during a chemical reaction called a precipitate
5. Energy is given off or absorbed (light, heat or sound)
[pic]
Materials:
20 ml of warm water
5 drops of phenol red solution
re-sealable plastic bag
2 scoops of calcium chloride
2 scoops of sodium bicarbonate (baking soda)
Procedure:
1. Pour 20mL warm water and 5mL phenol red solution into the bag. Seal the bag. Gently shake the bag. Feel the outside of the bag.
2. Carefully open the bag. Add 5mL of calcium chloride. Seal the bag and gently shake it. Feel outside of bag.
3. Record your observations
4. Carefully open the bag. Add 5mL baking soda. Seal the bag and gently shake it. Feel the outside of the bag.
5. Record your observations.
6. Observe the bag 10 minutes after you have completed steps 1-5 before recording final results.
Observation Chart:
|Step |Starting Materials |Starting Properties |Observations Once Combined |Physical or Chemical Change? |
|One |Phenol Red | | | |
| | | | | |
| |Warm Water | | | |
| | | | | |
|Two |Phenol Red and Warm Water | | | |
| |Calcium Chloride | | | |
| | | | | |
|Four |Previous Substance | | | |
| | | | | |
| |Sodium Bicarbonate | | | |
| | | | | |
|Six |10 Minutes After | |
| | | |
Analysis:
1. When I mixed water and phenol red I observed a (physical, chemical) change, because_______________________________________________________________________________________________________________________________________________.
2. When I added calcium chloride to the above mixture, I observed a (physical, chemical) change, because _____________________________________________________________
___________________________________________________________________________.
3. When I completed the final step of the lab experiment and added baking soda to the above mixture, I observed a (physical, chemical) change, because __________________________
_________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Science 14 Chapter 2 Review:
Vocabulary: Define each of the following terms:
a) Matter ________________________________________________________________
b) Pure substance ________________________________________________________
c) Mixture ________________________________________________________________
d) Periodic Table: _________________________________________________________
e) Metal __________________________________________________________________
f) Non-Metal ______________________________________________________________
Questions:
1. Describe the difference between each of the following terms:
a. Physical property and chemical property
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
b. Mixture and pure substance
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
c. A group and a period
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
d. An element and a compound
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
2. List three physical properties that make a golf ball different from a tennis ball.
3. Name two physical properties sugar and salt have in common
4. For each of the following, indicate whether a physical change or a chemical change has occurred.
a. Paper is cut__________________________________
b. Paper is burned_______________________________
c. A rubber band is stretched___________________________________
d. A cake is bakes____________________________________
e. Sugar is dissolved in water___________________________________
f. A match is lit____________________________________
5. Fill in the following chart
|Element name |Symbol |Period |Group |
|Cadmium | | | |
| |Zr | | |
| | |4 |1 |
| | |1 |1 |
| |O | | |
| |Nb |5 | |
6. Examine the periodic Table
a. How can you tell if an element is a metal or a non-metal?
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
b. How do the number of metal compare to the number of non-metals?
__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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What you will learn….
- How elements are organized in the periodic table
- How to tell whether a substance is a metal or a non-metal
- About the relationship between elements and compounds
- How to write element symbols and chemical formulas
- How elements and compounds are used in society.
But who cares?......
- Grouping substances with similar properties allows us to predict how substances might act. What you learn in this chapter will help you understand the short forms in the future science courses, on product labels, and in media reports.
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