1. Objective 3 Review
The student will demonstrate an understanding of the structures and properties of matter.

2. Parts of an Atom ELECTRON - PROTON + NUCLEUS ELECTRON CLOUD
NEUTRON no charge

3. An atom has a neutral charge
An atom has a neutral charge. Which of the following must be true about the atom?
It must have the same number of electrons and neutrons.
It must have more protons than electrons.
It must have the same number of electrons and protons.
It must have more neutrons than protons.
TMSDS 8.8A

4. Each atom has a different number of neutrons.
Look at the two atomic models below How can you tell that the two atoms represent different elements?
Each atom has a different number of neutrons.
Each atom has the same number of protons and neutrons.
Each atom has the same number of protons.
Each atom has a different number of protons.
TMSDS 8.8A

5. Ions and Isotopes ISOTOPES
The atoms have thesame number of protons, but have different numbers of neutrons. They have different masses. Isotopes can be radioactive.
IONS
The atoms have either lost or gained an electron in their outer shell and have an overall positive or negative charge. Ions are likely to undergo chemical reactions.

6. The sodium atom has an unequal number of protons and electrons
The sodium atom has an unequal number of protons and electrons. Why is it considered to be an ion with a +1 electrical charge?
The sodium atom has an extra electron, giving it a positive charge.
The sodium atom has an extra neutron, giving it a neutral charge.
The sodium atom has given up an electron, giving it a positive charge.
The sodium atom has given up a proton, giving it a positive charge.
TMSDS 8.8B

7. Element Keys ATOMIC NUMBER = # of PROTONS ELEMENT SYMBOL
The 1st letter is CAPS and if there is a 2nd letter it is lowercase.
ELEMENT NAME
ATOMIC MASS =
# of NEUTRONS + # of PROTONS

8. Carbon dioxide is a gas that is found in the air you breathe out
Carbon dioxide is a gas that is found in the air you breathe out. Carbon dioxide is made up of two different pure substances, carbon and oxygen. Which of the following would be classified as an element?
air
gas
oxygen
Carbon dioxide
TMSDS 7.7C

9. REMEMBER – GROUPS of elements have SIMILAR PROPERTIES!
Periodic Table
GROUP/ FAMILY (column)
PERIOD (row)

10. Use your periodic table to answer the following question
Use your periodic table to answer the following question. Which element on the periodic table has physical properties MOST similar to the physical properties of chlorine?
Sodium
Sulfur
Fluorine
Argon
TMSDS 8.9B

11. An element in Group 2 on the periodic table MOST likely has which physical property?
a dull rough surface in the solid phase
a boiling point far below 0°C
high malleability
low conductivity
TMSDS 8.9B

12. Organization
CHEMICAL CHANGE
PHYSICAL CHANGE

13. 4H2O Counting Atoms 4 molecules of water
NOTHING = the element symbol stand for 1 atom
COEFFICIENT = the number of molecules; multiply by everything in the formula
SUBSCRIPT = the number of atoms of that element

14. This is the chemical formula for a sample of matter: 3H2SO4 How many atoms of oxygen are found in this sample of matter? 3 4 7 12
TMSDS 8.9C

15. States of Matter Review

16. Physical vs Chemical Change
Chemical changes involve:
rusting / corrosion
reacting / reaction / digesting
burning / combustion
bubbling / fizzing / giving off a gas
***Everything else is a physical change***
(dissolving, boiling, melting, freezing, tearing, changing shape)

17. Maurice bought a bag of onions to make a large pot of onion soup
Maurice bought a bag of onions to make a large pot of onion soup. He cut the onions into small strips and then put them into a pot with butter to cook. Why was cooking the onion a chemical change, while cutting the onion was not?
Cutting the onion caused the shape of the onion to change.
Mixing the ingredients together created a chemical reaction.
Cooking the onion did not cause a permanent change in its molecular structure.
Cooking the onion caused a permanent change in its molecular structure.
TMSDS 6.7

18. Bubbles form as the two liquids mix together.
Mrs. Henderson conducts a class demonstration. She pours a test tube of a blue liquid into a beaker containing a clear liquid. Which of the following observations could be evidence that a chemical reaction does NOT take place?
Bubbles form as the two liquids mix together.
White powder settles on the bottom of the beaker.
The temperature of the liquid increases.
The temperature of the beaker remains the same after the liquids mix.
TMSDS 8.9A

19. Chemical Reactions REACTANTS PRODUCTS
You show a chemical reaction with a CHEMICAL FORMULAS and EQUATIONS.
Carbon dioxide + water + sunlight = sugar + oxygen
6CO2 + 6H2O + light → C6H12O6 + 6O2
REACTANTS
They “REACT” together.
PRODUCTS
They are “PRODUCED” by the reaction.
The arrow means “equals”

20. A student researches the chemical reaction that forms a certain kind of plastic. Which format is BEST for summarizing information about the reaction?
A chemical formula
A chemical equation
A data table
A written paragraph
TMSDS 8.9C

21. Endothermic/Exothermic
Heat must be added to make the chemical reaction happen.
It is written as a reactant.
EXOTHERMIC
Heat is produced during a chemical reaction. The temperature will go up.
It is written as a product.
Reactants + HEAT → Products
Reactants → Products + HEAT

22. Water has a higher specific heat than land.
The amount of energy it takes to raise the temperature of 1 gram of a substance 1 oC.
It is a physical property and depends on how much of the substance you have.
Water has a higher specific heat than land.
The land heats up and cools off more quickly – lower specific heat.
The water heats up and cools off more slowly – higher specific heat.

23. Law of Conservation of Mass
During a chemical change (reaction), the total mass stays the same, even though it may change forms.
Ex: If you start with 5 grams of Zn and 2 grams of Oxygen and it all completely reacts to form ZnO, there must be ___ grams of ZnO formed.
The number of each type of atom on each side of the equation must always be equal.
Ex: ___ H2 + ___ O2  ___ H2O 7 2 2