Mr. Huang Science 10

Unit 1: Chemistry

1. Atomic Theory 2. Periodic Table 3. Isotopes and Radioactive Particles 4. Half-life 5. Chemical Formula for Ionic Compounds 6. Chemical Formula for Molecular Compounds 7. Law of Conservation of Mass 8. Balancing Chemical Reaction 9. Types of Reactions 10. Ionic vs. Covalent Bonding 11. Acid,Base,Salt,pH 12. Collision Theory and Reaction Rates

This note package belongs to ____________________

Mr. Huang

Science 10 Atomic Theory

Jeffrey Huang 1

Chemistry

Lesson

1 History of the Atom

1800: John Dalton

1898: J. J. Thompson 1911: Ernest Rutherford 1913: Neils Bohr

Bohr Model Although Neils Bohr’s model is no longer the correct model of the atom, we still use the Bohr model in our study of how an atom works. It is the simpler way of looking at an atom without going into high level math and calculus. Chemical Symbols on the Periodic Table

[Text Reference: 4.1 Atomic Theory and Bonding] Goal 1: Be able to read and draw a Bohr model of an Atom

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How to Draw Bohr Models of the Element Let’s begin our practice with Fluorine.

• How many protons does it have? __________

• How many electrons does it have? ___________ Step 1: Label the center of the diagram with the atomic number and symbol for the element Step 2: Determine the number of shells needed. Remembering that 1st shell can have 2 electrons while the 2nd and 3rd shell can have 8 electrons. Step 3: Fill the first shell with 1 set of paired electrons Step 4: Place as many electrons as needed into the second shell (maximum is 8 electrons). Fill each position (top, bottom, left, right) with one electron before pairing them up. Continue on to third shell (maximum 8 electrons) if needed Now let’s practice with new more elements: 1) Sulphur 2) Calcium

Mr. Huang

Science 10 Periodic Table

Jeffrey Huang 3

Chemistry

Lesson

2 Looking at the Periodic Table Let’s look at it with more details….

Going Across the Periodic Table:

Going Down the Periodic Table:

[Text Reference: 4.1 Atomic Theory and Bonding] Goal 2: Understand how the periodic table was assembled

Goal 3: Describe the properties of elements as grouped on the periodic table Goal 4: Understand the relationships between the subatomic particles of an atom

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Alkali Metals Lithium (Li) Sodium (Na) Potassium (K) Rubidium (Rb) Cesium (Cs) Francium (Fr)

Alkaline Earth Metals Beryllium (Be) Magnesium (Mg) Calcium (Ca) Strontium (Sr) Barium (Ba) Radium (Ra)

Transition Metals Metals in the middle of the periodic table

Halogens Fluorine (F) Chlorine (Cl) Bromine (Br) Iodine (I) Astatine (At)

Nobel Gases Helium (He) Neon (Ne) Argon (Ar) Krypton (Kr) Xenon (Xe) Radon (Rn)

Using the Periodic Table

Symbol #

protons # electrons # neutrons Atomic number

Atomic mass

Charge on nucleus

Charge on atom/ion

𝑀𝑔1224

𝐾+1939

𝑂2−816

26 30 3+

38 38 88

31 +25 0

17 35 1-

88 126 4+

Mr. Huang

Science 10 Isotopes and Radioactive Particles

Jeffrey Huang 5

Chemistry

Lesson

3 Radiation

• We’ve often heard of the word “radiation” in movies or TV shows, but what exactly is radiation?

• There are many forms of radiation. Visible light is a form of radiation. Some radiation are harmful to us, some aren’t.

Isotopes

• Once neutrons were discovered, scientists found out that sometimes the ________________________ would have ________________________. This was because these elements differ in the number of ___________. These elements were said to be ________________ of one another

• This is important to our study of radioactivity because certain isotopes of the same element can be _______ or _____________. Hence, we can clarify our previous statement that radiation is a result of unstable isotope ______________ to a stable isotope.

Isotopes: ______________________________________________________________

[Text Reference: 7.1 Isotopes and Radioactive Decay] Goal 5: Define and explain what radiation is

Goal 6: Define and explain what isotopes are Goal 7: Understand the 3 different types of radioactive decay

Radiation: ______________________________________________________

____________________________________________________________________

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Radioactive Materials

• Interestingly enough, certain isotopes of elements were found to be radioactive and highly unstable. These particles would undergo radioactive decay, or what we commonly call: _______________________

1. Alpha Decay

• Alpha decay occurs when a radioactive atom emits an alpha particle

• It has 2 ____________ and 2 _____________, identical to a _______________ nucleus

Radioactive decay: ______________________________________________________

____________________________________________________________________

Example:

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2. Beta Decay

• Beta decay occurs when a radioactive atom emits an beta particle

• It has only 1 _________ and is identical to an _____________ 3. Gamma Decay

• In gamma decay, the nucleus emits light rays

• These rays are very high in energy

• Usually, alpha and beta decay leads to a nucleus that would be _____________________ (excited). This energy is released as gamma ray so that the nucleus would go back to a ___________________

Example: Write the nuclear equation for the alpha decay of americium-241

Example: Write the nuclear equation for the beta decay of cesium-137

Example: Write the nuclear equation for the beta decay of boron-12 to an excited nucleus

Mr. Huang

Science 10 Half-Life

Jeffrey Huang 8

Chemistry

Lesson

4 Half-Life

• We learned from the previous class that certain isotopes of elements are radioactive, meaning that they will undergo either alpha, beta, and/or gamma decay. Half-life is the amount of time it takes for ________ of a ________________________. Different isotopes and different elements have different half-life’s. In other words, certain material __________________ than other materials

Number of Half-lives

Fraction remaining

Percent remaining

Half-life: ______________________________________________________________

_____________________________________________________________________

Example: Cesium-124 has a half-life of 31 seconds. A sample of cesium-124 in a laboratory has an initial mass of 20 g a) Calculate the amount of time it will take for the sample to decay to 5 g b) Calculate how much cesium-124 will remain after 93 s

[Text Reference: 7.2 Half-Life] Goal 8: Explain the process of half-life

Goal 9: Understand how radioactive dating works

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Decay Series

• Sometimes the _______________________________. Then it will undergo __________________________ in-attempt to become stable. When radioactive nuclei form such a _______________________ of radioactive decay, we call it a decay series. Observe the following diagram

Radioactive Dating

• Once we know the half-life of a radioactive isotope, we can use this knowledge to _________________________. _________________, with a half-life of _______________, is often used to date old materials left on Earth. When a living organism dies, no new carbon-14 will enter the organism. As a result, Carbon-14 will begin to decay. By __________________________ of Carbon-14 remaining in the organism, we can use its half-life to determine how old the organism is…..kind of like what we just did!

Example: A piece of leather was found to have 12.5% of its original carbon-14 present. Determine the age of the leather using the figure below and by calculations

Mr. Huang

Science 10 Chemical Formula for Ionic Compounds

Jeffrey Huang 10

Chemistry

Lesson

5 A) Writing Formula

1. Example: Write sodium sulfide as its chemical formula

Step 1: Determine the symbol of the first element.

Step 2: Determine the symbol of the second element. Remember, the ending “ide” means that the name

represents an element on the periodic table. Look for the element with the same beginning to its name.

Step 3: Place the two symbols side-by-side in order and write their charge (found from the periodic table) at

the top right of each elements’ symbol. Ignore the + or - at this point.

Step 4: Cross over the charges so that the number becomes the subscript

Step 5: Reduce the subscripts if they have a common factor and delete all the “1”.

2. Example: Write ammonium sulfate as its chemical formula

**Notice that ammonium and sulfate are not elements! They are polyatomic ions! It looks hard, but the

procedures are the same.

Step 1: Determine the symbol of the first part

Step 2: Determine the symbol of the second part

Step 3: Place a bracket around each polyatomic ion. Use the charge and cross over:

Step 4: Reduce the subscripts if they have a common factor. Delete all the “1” and remove brackets if there

are no subscripts following them.

Ionic Compound: A compound where the first element is a metal followed by a non-metal

[Text Reference: 4.2 Names and Formulas of Compounds] Goal 10: Know how to name and write chemical formulas for Ionic Compounds

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3. Example: Write iron (III) chloride as its chemical formula

**Notice that there is a (III) following iron. All transition metals could have more than 1 charge. Iron here,

can either be 2+ or 3+. Therefore, the (III) tells us what charge this iron will be!

Step 1: Determine the symbol of the first part

Step 2: Determine the symbol of the second part

Step 3: Place a bracket around each polyatomic ion. Use the charge and cross over:

Step 4: Reduce the subscripts if they have a common factor. Delete all the “1” and remove brackets if there

are no subscripts following them.

B) Naming a Formula

1. Example: Write Na2O as its chemical name

Step 1: Find the first element on the periodic table

Step 2: Find the next element in the compound, but change its ending to “ide”

Step 3: Place the two names in order with a space

Example: Write the formula for these ionic compounds a) copper (II) chloride b) lead (IV) oxide

c) aluminum sulphide d) copper (II) hydroxide

e) gold (III) sulfate f) aluminum phosphate

g) potassium oxide h) calcium nitride

i) magnesium phosphide j) ammonium phosphate

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2. Example: Write Cu2O as its chemical name

**Cu has two possible charges!

Step 1: Uncross the chemical name to figure out the charges of the first element

Step 2: Write the first element followed by its charge in Roman numerals in brackets

Step 3: The rest is the same

3. Example: Write (NH4)2CO3 as its chemical name

**Use your list of polyatomic ions on the back of your periodic table

Step 1: Name the first part of the compound

Step 2: Name the second part of the compound, but if it is not an element, don’t change the ending to “ide”

Step 3: Put the two names together in order

Example: Write the formula for these ionic compounds a) Cs2Se b) AgBr

c) Al2O3 d) AuN

e) SnO2 f) MnS2

g) K2SO4 h) NH4OH

i) Sr(ClO3)2

Mr. Huang

Science 10 Chemical Formula for Molecular Cmpds

Jeffrey Huang 13

Chemistry

Lesson

6 A) Writing Chemical Formula

1. Example: Write sulfur hexafluoride as its chemical formula

Step 1: Look at the first part of the name to identify the element and the number of them you need to

include. If there is no prefix, that’s the same as “mono” or one.

Step 2: do the same thing for the second part

Step 3: Ignore charges. Do not cross over. Just write the numbers as subscripts

Here is a list of prefixes

Prefix Value

Mono 1

Di 2

Tri 3

Tetra 4

Penta 5

Hexa 6

Hepta 7

Octa 8

Nona 9

Deca 10

Molecular Compound: A compound where the first element is a non-metal followed by a non-metal

Example: Write the formula for these molecular compounds a) Boron tribromide b) dinitrogen pentaselenide

c) carbon monoxide d) Phosphorous trichloride

[Text Reference: 4.2 Names and Formulas of Compounds] Goal 11: Know how to name and write chemical formulas for Molecular Compounds

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B) Naming Compounds

1. Example: Write CCl4 as its chemical name

Step 1: Do not use charges!

Step 2: Use prefixes (from the table before) to give the number of each element

Step 3: If the first element has “mono” as its prefix, you can ignore it. Don’t forget to change the ending of

the second element

Example: Write the formula for these molecular compounds a) N2Cl5 b) SO3

c) AsI4 d) XeF6

Mr. Huang

Science 10 Law of Conservation of Mass

Jeffrey Huang 15

Chemistry

Lesson

7 Reaction 1:

Reaction 2:

[Text Reference: 4.3 Chemical Equations] Goal 12: Understand how the Law of Conservation of Mass applies to chemical

reactions

Mr. Huang

Science 10 Balancing Chemical Reactions

Jeffrey Huang 16

Chemistry

Lesson

8 Chemical Reactions

HCl + Na2CO3 NaCl + H2O + CO2 Law of conservation of Mass states that in a closed system, no atoms will be gained or loss. However, if we try to count the atoms in that chemical equation, we notice that the atoms don’t balance out! So, what we will learn now is to balance chemical equations! Example 1: Balance the following equation: HCl + Na2CO3 NaCl + H2O + CO2

Step 1: Write down the number of each element present on each side of the equation.

HCl + Na2CO3 NaCl + H2O + CO2

Step 2: Balance one of the elements (REMEMBER THAT YOU MAY ONLY PLACE NUMBERS IN FRONT OF THE CHEMCIAL FORMULA DN THAT YOU MAY NOT CHANGE THE FORMULA)

HCl + Na2CO3 NaCl + H2O + CO2

Step 3: Check to see if any other elements are sill unbalanced and if so, balance ONE of them

HCl + Na2CO3 NaCl + H2O + CO2

Other Steps: repeat this process as many times as necessary, always changing one at a time until ALL of the elements are balanced. The equation is then balanced and we can all sleep safe knowing that the Law of Conservation of Mass is preserved!

[Text Reference: 4.3 Chemical Equations] Goal 13: Balance chemical equations according to the Law of Conservation of Mass

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You Try! Example 2: Fe + CuSO4 Fe2(SO4)3 + Cu Example 3: Al + HCl AlCl3 + H2 Example 4: AlBr3 + K KBr + Al Word Problems Now let’s make things a little harder! Now that we are competent in writing chemical formulas and balancing, let’s put them together: Write a balance reaction for the following chemical reactions: Example 1: Sodium metal reacts with water to form sodium hydroxide and hydrogen gas Example 2: Zinc metal reacts with copper (II) sulfate to produce zin sulfate and copper metal Example 3: Hydrogen Chloride reacts with barium fluoride to produce hydrogen fluoride and barium chloride

Mr. Huang

Science 10 Types of Chemical Reactions

Jeffrey Huang 18

Chemistry

Lesson

9

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[Text Reference: 6.1 Types of Chemical Reactions] Goal 14: Explain and describe the different types of chemical reactions

Mr. Huang

Science 10 Ionic Vs. Covalent Bonding

Jeffrey Huang 19

Chemistry

Lesson

10

Introduction

• Why do atoms bond with other atoms in the first place?

• There are 2 ways to achieve this “noble” objective

1) ________________________ and form __________ compounds

2) ________________________ and form __________ compounds

Ionic Bonding

• Ionic bonding involves the formation of ____________ and ____________ ions. This happens

easily for atoms which only have a few electrons to __________ or a few electrons to __________

to obtain a ____________________.

• These ions are then attracted to each other by strong _____________________ and form

_____________ compounds. These compounds tend to form as __________________________

Important: There is NO NaCl molecule. The formula of ionic compounds I just

a ratio of the ions which are attracted together. You don’t see the individual

“NaCl” molecules. You see a whole network/cube of Na+ and Cl- ions.

What does MgCl2 look like:

• How does the formation of ionic crystals explain the properties of ionic compounds?

[Text Reference: 4.1 Atomic Theory and Bonding] Goal 15: Understand how Ionic bonds are formed

Goal 16: Understand how covalent bonds are formed

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Covalent Bonding

• Covalent bonding involves the sharing of electrons to form ________________

• This happens typically for atoms of ________________, for example ___________, __________

and _________.

• Eg.

• Notice once again the “noble” objective is achieved

• How does the formation of covalent molecules explain the properties of covalent compounds?

Mr. Huang

Science 10 Acid/Base/Salt/pH

Jeffrey Huang 21

Chemistry

Lesson

11

Classifying Compounds

pH Scale

• How do we tell if one chemical is more acidic than the other? We use an acidity scale called the pH Scale.

There are a few key points to remember about this scale:

1. pH is from _____ to _______

2. pH of 7 is ___________

3. pH less than 7 is _____________( 0 being most __________)

4. pH greater than 7 is ___________ (14 being most ___________)

Example: Classify the following compounds as Acid, Base, Salt or Covalent Compound

a) Na3PO4 b) Al(OH)3

c) Ca(OH)2 d) H3PO4

e) CaCl2 f) CH3CH2COOH

g) CO2 h) C10H22

[Text Reference: 5.1 Acids and Bases, 5.2 Salts] Goal 17: Be able to classify the different types of compounds

Goal 18: Understand the similarities and differences between acids and bases

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Acids vs Bases

Naming Them

Properties

Acids:

__________________________________

__________________________________

__________________________________

Bases:

__________________________________

__________________________________

__________________________________

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Reactions

1. Acid base neutralization

• Acid + Base Salt + Water

• HCl + NaOH NaCl + H2O

2. Oxides

3. Acid and Metals

Mr. Huang

Science 10 Collision Theory and Reaction Rates

Jeffrey Huang 24

Chemistry

Lesson

12

Collision Theory

• We are going to assume that all molecules act as ___________________________. They are constantly

moving and when they _________, they will bounce off each other and __________ energy. If the

molecules or particles hit each other with enough force, they may combine.

• Consider the following reaction and diagram:

H2 + I2 2HI

• When the molecules react, they hit each other and for a split second, they will stick together to form what we can an __________________________. This intermediate molecule may then ____________________ two (or more) new molecules.

• With this realization, we come to the first rule for collision theory:

Factors Affecting Reaction Rate

1. Temperature

• When temperature ____________, the time of reaction _____________. This means that it takes ______

time for the reaction to finish. Therefore when temperature increases, the reaction rate _____________.

• Using collision theory, we explain by saying that at higher temperatures, particles will have more

________ energy. When particles are moving faster, there are more __________ for collisions to occur.

Hence reaction rate increases.

• Note: Temperature _______________ increases reaction rate.

Rule 1: ____________________________________________________________________________________

__________________________________________________________________________________________

Memorize this!!!

[Text Reference: 6.2 Factors Affecting Reaction Rates] Goal 19: Describe what the collision theory is and how it relates to chemical reactions

Goal 20: Describe the different factors that affect reaction rates

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2. Concentration.

• When reactant concentration __________, the time of reaction ___________. This means that it takes

_______ time for the reaction to finish. Therefore, when reactant concentration increases, the reaction

rate _____________.

• Using collision theory, we explain by saying that as concentration of a reactant increases, there will be

more _______________________ between reactants. Therefore, reaction rate will ___________

3. Surface Area

• When the surface area increases, _____________ is available for reactants to react. This means that it

takes ___________ for the reaction to finish. Therefore, when surface area increases the reaction rate

_____________

• Using collision theory, we explain by saying that when the surface area increases, there will be more

________________________________________. Therefore reaction rate will increase.

4. Catalyst and Inhibitors

• Note: Catalysts are not part of the reaction. This means that at the end of the reaction, you will get back

all the catalyst you added in the beginning. Think of it as a tool.

• Example: poisons (they prevent your body reactions from working) or antibiotics (they prevent bacterial

reactions from working)

Catalyst: ______________________________________________________________________ ______________________________________________________________________________________

Inhibitors: _____________________________________________________________________ _____________________________________________________________________________________