An Introduction 1.

An Introduction 1

Why is Chemistry Important?
In Our Daily Lives New Materials New Pharmaceuticals New Energy Sources Food Supplies 2

Chemistry deals with the natural world.
Source: Terry Donnelly/Stone/Getty Images

What is Chemistry? The science that deals with the materials of the universe~ and the changes these materials undergo *Understanding most other fields of science requires an understanding of Chemistry 4

The launch of the space shuttle gives clear indications that chemical reactions are occurring.
Source: NASA

The Best Approach to Learning Chemistry
Learn the Vocabulary of Chemistry Definitions of Terms Memorize Important Information Atoms~elements~compounds~molecule Learn and Practice Processes Names and Formulas~the periodic table 12

MATTER & ENERGY Matter is the part of the universe that has mass and volume Energy is the part of the universe that has the ability to do work Chemistry is the study of matter The properties of different types of matter The way matter behaves when influenced by other matter and/or energy 3

Matter Anything that has mass and takes up space (volume) Examples:
A brick has mass and takes up space A desk has mass and takes up space A pencil has mass and takes up space Air has mass and takes up space All of the above examples are considered matter because they have mass and take up space. Can you think of anything that would not be considered matter?

States of Matter solid, liquid, gas 7

The Building Blocks of Matter: Atoms
- - - + + + + - - + + - - -

Atoms Smallest possible unit of mater while still maintaining its properties. Made up of: protons neutrons electrons The solar system is commonly used as an analogy to describe the structure of an atom - + - + + + - + __ -

+ Protons (+) Positively charged particles Part of the nucleus
Helps identify the atom (sort of like an atom’s DNA) Equal to the atomic number Contributes to the atomic mass Equal to the number of electrons + - +

Neutrons Neutral particles; have no electric charge
Help make up the nucleus of the atom Contribute to the atomic mass + -

- Electrons (-) Negatively charged particles
Found outside the nucleus of the atom, in the electron orbits/levels; each orbit/level can hold a maximum number of electrons ( 1st = 2, 2nd = 8, 3rd = 8 or 18, etc…) Move so rapidly around the nucleus that they create an electron cloud Mass is insignificant when compared to protons and neutrons Equal to the number of protons Involved in the formation of chemical bonds + - -

Hydrogen (H) Atom - Notice the one electron in the first orbital = 1 +
= 0 - How many more electrons can fit in the 1st orbital/ level? + Even though there are no neutrons present, Hydrogen is still considered an atom

Oxygen (O) Atom Notice the two electrons in the first orbital/level and the six in the second + - = 8 How many more electrons can fit in the 2nd orbital/ level? - - - + + + + - - + + - - -

Sodium (Na) Atom Notice the two electrons in the first orbital/level, eight in the second, and one in the third + - = 11 = 12 - - - How many more electrons can fit in the 3rd orbital/ level? - + + + + - - - + + - - - -

What would be the atomic number of this atom?
The number of protons in the nucleus of an atom - What would be the atomic number of this atom? + - -

+ Mass Number + What would be the mass number of this atom? - - -
The total number of protons and neutrons in an atom’s nucleus Expressed in Atomic Mass Units (amu) Each proton or neutron has a mass of 1 amu What would be the mass number of this atom? - +  3  4 + - 3 protons + 4 neutrons = a mass number of 7 amu Why did we not account for the electrons when calculating the mass number? -

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Additional video resource: bev.shone ocwaves2016

Isotopes Atoms that have the same number of protons, but have different numbers of neutrons Examples Notice that each of these atoms have one proton; therefore they are all types of hydrogen. They just have a different mass number (# of neutrons). - - + + + - Hydrogen (Protium) Hydrogen (Deuterium) Hydrogen (Tritium)

Ion Charged particle that typically results from a loss or gain of electrons Two types: Anion = negatively charged particle Cation = positively charged particle - - - + - = 8 + + + + - - 9 6 + + - - Now that three electrons were lost, the number of electrons (6) and protons (8) is still unbalanced; therefore, it is still an ion, but now it is specifically referred to as a cation. Now that this atom of oxygen just gained an electron, it is no longer neutral or an atom. It is now considered an ion (anion). This ion has more electrons (9) than protons (8). Currently, this atom of oxygen is neutral because it has an equal number of electrons (8) and protons (8). - - Symbol = O1- Symbol = O2+ Symbol = O

Atomic Theory Because we can not see atoms, we use models to teach and learn about atoms. The atomic theory has changed over time as new technologies have become available. Remember: Scientific knowledge builds on past research and experimentation.

Atomic Theory Timeline
Scientist Information Model John Dalton All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

Scientist Information Model J.J Thompson Discovered the negative electron, and predicted that there also must be a positive particle to hold the electrons in place.

Scientist Information Model Ernest Rutherford Discovered the nucleus of an atom and named the positive particles in the nucleus “protons”. Concluded that electrons are scattered in empty space around the nucleus.

Scientist Information Model James Chadwick Discovered that neutrons were also located in the nucleus of an atoms and that they contain no charge. Neutrons

Scientist Information Model Neils Bohr Concluded that electrons are located in planet-like orbits around the nucleus in certain energy levels.

Scientist Information Model
(Many Scientists!) The Modern Atomic Theory Electrons do not orbit the nucleus in neat planet-like orbits but move at high speeds in an electron cloud around the nucleus.

bev.shone ocwaves2016

Objectives: Atoms and Elements
There are billions of materials in our universe. Those materials are made up from about 100 elements only.

An element is a substance that is made from one kind of atom only
An element is a substance that is made from one kind of atom only. It cannot be broken down into simpler substances. atom atom An element An element

A compound is a substance that is made from more than one element.
atom atom A compound made up of 2 different elements A compound made up of 7 different elements

A compound can be broken down into elements
An element An element A compound made up of 3 different elements An element

Draw a line between the molecule and its name.
Hydrogen chloride HCl Chlorine Cl2 Carbon dioxide CO2 Methane CH4

Water Coal Carbon dioxide Oxygen Chalk Wax Table salt Caffeine
Material Made up of: Element or compound Water Hydrogen and Oxygen Coal Carbon Carbon dioxide Carbon and Oxygen Oxygen Chalk Calcium, Carbon & Oxygen Wax Carbon & Hydrogen Table salt Sodium & Chlorine Caffeine Carbon, Hydrogen, Nitrogen & Oxygen

Water Compound Coal Element Carbon dioxide Oxygen Chalk Wax Table salt
Material Element or compound Water Compound Coal Element Carbon dioxide Oxygen Chalk Wax Table salt Caffeine

7th Grade Science Understanding the Periodic Table

bev.shone ocwaves2016

Electrons & the Periodic Table
Electrons in all atoms are arranged around the nucleus in regions called energy levels The largest atoms have as many as seven energy levels Energy Levels

The outermost energy level is called the valence shell The electrons in the valence shell are called valence electrons Energy Levels

Elements are grouped because they have similar properties In some groups, the elements all have the same number of valence electrons in their atoms

In atoms of elements in Groups 1 & 2, the number of valence electrons matches the group number

In atoms of elements in Groups 13-18, the number of valence electrons is 10 fewer than the group number

Atoms of elements in Groups 3-12, the Transition Metals, do not follow a general rule In addition, helium atoms only have 2 valence electrons

Why Do I Need the Periodic Table?
What Do You Think? What similarities exist between you and the other members of your family? How about between you and your classmates?

Grouping the Elements - Group 1
Group 1: Alkali Metals- 1 Valence Electron All metals except Hydrogen, the Group 1 elements, are the most reactive.

Group 1: Alkali Metals- 1 Valence Electron This means that the atoms of these elements are not stable and will lend valence electrons to other atoms.

Group 1: Alkali Metals- 1 Valence Electron These elements are never found uncombined in nature.

Alkali Metals Compounds formed from Alkali metals have many uses for humans NaCl, or Sodium Chloride, is table salt that is used to season your food Potassium compounds are found in bananas

Group 2: Alkaline-Earth Metals- 2 Valence Electrons Alkaline-Earth metals are very reactive, but not as reactive as Alkali metals.

Group 2: Alkaline-Earth Metals- 2 Valence Electrons This is because it is harder for their atoms to lose 2 valence electrons than for the Alkali metals to lose 1

Group 2: Alkaline Earth Metals Magnesium is mixed with other metals to make rims on cars. Calcium is an important part of the compound that keeps your bones and teeth healthy.

Grouping the Elements Groups 3-12
Groups 3-12: Transition Metals Groups 3-12 do not have individual names.

Groups 3-12 are all grouped together as the Transition Metals.

Groups 3-12 The Transition Metals are less reactive than Groups 1 & 2 because they don’t lose their valence electrons as easily. Groups 3-12

Silver and Gold are Transition Metals.
Grouping the Elements Silver and Gold are Transition Metals.

Grouping the Elements Transition Metals Iron, Cobalt, and Nickel, all Transition Metals, are the only elements known to produce a magnetic field.

The most common element from Group 13 is aluminum.
Group 13: Boron Group The most common element from Group 13 is aluminum.

Group 13 Aluminum was considered more precious than gold or silver until the 1880s, when plentiful electricity made it cheaper. Aluminum is used to make cans, cars, and airplanes.

The nonmetal Carbon, in Group 14, is often found uncombined in nature.
Group 14: Carbon Group The nonmetal Carbon, in Group 14, is often found uncombined in nature.

Group 14 Carbon forms both diamonds and charcoal. Carbon also forms a wide variety of compounds such as proteins, fats, and carbohydrates, all necessary for life on earth.

Group 15 Group 15: Nitrogen Group Nitrogen, a gas at room temperature, makes up about 78% of the air you breathe.

Nitrogen from the air is combined with Hydrogen to make fertilizer.
Group 15 Group 15: Nitrogen Group Nitrogen from the air is combined with Hydrogen to make fertilizer. Fertilizer helps grow the crops that feed us all.

Oxygen, in Group 16, makes up about 21% of the air you breathe.
Oxygen is very reactive, combining with many other elements such as iron and carbon.

Group 16 Sulfur, another common member of Group 16, is used to make sulfuric acid for car batteries.

Halogens are the very reactive nonmetals in Group 17.
They react easily because their atoms only need to gain 1 electron to have a complete set

Group 17 Chlorine is a yellow halogen that is used to disinfect water for drinking and swimming

Noble gases are unreactive nonmetals in Group 18.
These elements’ atoms have full outermost energy levels, and cannot react with other elements

Noble gases like neon glow when electrically charged.
Group 18 Noble gases like neon glow when electrically charged. Argon in a light bulb keeps the filament from burning out.

Let’s Review! 1 - How does the periodic table help you identify the physical properties of elements?

How are elements grouped on the periodic table of elements?
Let’s Review! 2 - How are elements grouped on the periodic table of elements?

The Periodic Table Objective:
To learn the symbols and properties of 20 elements in the periodic table.

The Periodic Table is a useful way to arrange elements.
The vertical columns are called groups. The horizontal rows are called periods. Elements in the same group have similar properties. Three quarters of the elements are metals. One quarter of the elements are non-metals.

Rules for chemical symbols in the periodic table:
The symbol is usually the first one or two letters of the name. Sometimes the old (Latin) name is used . The first letter of a symbol id always a capital letter. The second letter of a symbol is always a small letter. Every element has a different symbol.

Now look in your periodic table and find the symbols of the following elements, then find out if it is a metal or a non-metal: Copper …….. Iron ……….. Magnesium ……….. Chlorine ……….. Carbon ………… Sodium ……. Lead ………. Gold ……… Calcium …….. Fluorine ……….

Now look in your periodic table and find name that corresponds to the following symbol:
Fe …….. Mg ……….. Ag ……….. K ……….. C ………… Ca ……. Na ………. N ……… Ne …….. Pb ……….

The Periodic Table Q1. The symbol of Nitrogen is: a. Na b. N c. Ni
Q2. Hg is the symbol of: a. Hydrogen b. Helium c. Mercury Q3. The percentage of metals in the periodic table is: a. 75% b. 50% c. 25% Q4. Water is not in the periodic table because: a. It is a liquid substance b. It is a natural substance c. It is a compound not an element

The Periodic Table Objective:
To learn the symbols and properties of 20 elements in the periodic table.

Q1. Name a metal in group 1 that is in the same period as Magnesium.
Q2. Name a metal in group 2 that in the same period as Lithium. Q3. Name a non-metal in the same group as Nitrogen. Q4. Name a noble gas in the same period as Oxygen. Q5. Name a gas in group 7 that is in the same period as Aluminium.

Objective: 1. Learn the scientific method for naming compounds. 2. There are three rules for naming compounds: the “ide” rule, the “ate” rule and the “same” rule.

Cl Na Mg O Fe S Sodium Chloride Magnesium Oxide Iron Sulphide
Rule 1: When two elements combine the ending is usually ” ……………ide”. metal goes first Sodium Chloride Magnesium Oxide Iron Sulphide Cl Na Mg O Fe S

Rule 2: When three or more different elements combine and one of them is Oxygen, the ending will be “………ate”. metal goes first Copper Sulphate Calcium Carbonate O O Cu S O O O O C Ca O

Rule 3: When two identical elements combine, the name does not change.
H2 = Hydrogen F2 = Fluorine N2 = Nitrogen Cl2 = Chlorine O2 = Oxygen H F N Cl O

Name the following compound
Na2O

CuSO4

MgSO4

ZnO

MgCl2

Name the following molecule

KI

AgNO3

Fill in the blanks: Magnesium + ……………. Magnesium oxide
……………….. + Iodine Hydrogen ………….. ……………. + Oxygen Iron oxide Copper oxide + Carbon ………….. + Carbon dioxide

Objectives: 1. In all chemical equations the reactants turn into products and we have an arrow between the two as shown here: Reactants Products

The Reaction The thermit reaction is used by the railway engineers to mend cracked iron rail. It is a very useful reaction between Aluminium and Iron oxide to produce Aluminium oxide and Iron. Aluminium + Iron oxide Aluminium oxide + Iron The reaction gives out a lot of heat, enough heat to melt the Iron produced which can be therefore poured into the gaps in the rails.

Copy down the following equations in your book
Copy down the following equations in your book. Underline the reactants and circle the products in each of the equations: Magnesium + Oxygen Magnesium oxide Iron + Oxygen Iron oxide

When you react Magnesium with Oxygen you get:
Oxygen magnesimide b. Magnesium oxygen Magnesium oxide d. Magnesium oxate 2. One of the products of the thermit reaction is: Iron oxide b. Aluminium c. Carbon d. Iron 3. Sodium is in the same group as: Magnesium b. Aluminium c. Potassium d. Neon 4. The colour of Magnesium oxide is: White b. Black c. Silver d. Brown 5. Calcium Carbonate does not contain: a. Hydrogen b. Oxygen c. Carbon d. Calcium

Copy down the following equations in your book
Copy down the following equations in your book. Underline the reactants and circle the products in each of the equations: Magnesium + Oxygen Magnesium oxide Calcium carbonate Calcium Oxide + Carbon dioxide Iron + Bromine Iron bromide Aluminium + Chlorine Aluminium Chloride Iron + Oxygen Iron oxide Lead oxide + Carbon Lead + Carbon dioxide

What is the name of the reaction used by the railway engineers to mend cracked iron rails?
What are the reactants of that reaction? What are the products of that reaction?

Draw a line between the molecule and its name.
Hydrogen chloride HCl Chlorine Cl2 Carbon dioxide CO2 Methane CH4

Chemical Reactions Objectives: 1. The formula of a compound shows the number and the type of atoms in it. 2. A small number after the symbol for each element in a compound shows how many atoms each molecule contain.

Draw a line between the compound and its name:
MgCl2 Magnesium Carbonate NaCl Zinc Fluoride Pb(NO3)2 Magnesium Chloride FeS Iron sulphide CaCO3 Lead nitrate CuSO4 Copper sulphate ZnF2 Potassium Iodide MgCO3 Sodium Chloride KI Calcium Carbonate

1. How many atoms of Hydrogen in one molecule of Methane CH4 ?
2. How many atoms of Nitrogen in one molecule of Lead nitrate Pb(NO3)2 ? 3. Sodium oxide has two atoms of sodium for every atom of oxygen. What is the formula for sodium oxide? 4. Magnesium chloride has one atom of Magnesium for every two atoms of chlorine. What is the formula for Magnesium chloride? 5. How many atoms of Nitrogen in one molecule of Ammonia NH3 ?

How many atoms of Oxygen is there is two molecules of CuSO4 ?
b c d. 8 2. Oxygen will: turn limewater milk b. relight a glowing splint c. burn with a squeaky pop d. put out a glowing splint 3. How many atoms are there altogether in one molecule of MgCl2 ? b c d. 6

Chemical Reactions Objectives: 1. The number of atoms in the reactants are equal to the number of atoms in the products.

Mg + 2 HCl MgCl2 + H2 What are the reactants of the above reaction?
What are the products?

Mg + 2 HCl MgCl2 + H2 Give me your Chlorine and get out of here. H H

Mg + CuO MgO + Cu Give me your Oxygen and get out of here. Cu Oxygen

Carbon dioxide Oxygen Hydrogen relights a glowing splint
Test for gases Draw a line between the name of the gas and the method to test for it. relights a glowing splint Carbon dioxide burns with a squeaky pop Oxygen Hydrogen turns limewater cloudy

An Introduction 1.

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