*Basic Building Materials

Unit 1, Section 2

* Lesson 6 A New Language

* Lesson 7 Now You See It

* Lesson 8 What Goes

Around Comes Around

* Lesson 9 Create a Table

* Lesson 10 Breaking the

Code

*Lesson 6: A New

Language

You will be able to:

• define new terms

• recognize whether a substance is

an element or a compound based

on its chemical formula or symbol

• decipher some basic chemical

formulas and symbols

*vocabulary

* Element

* Compound

* Aqueous

* Chemical formula

*Key Question

* What do chemical names, formulas and

symbols tell you about matter?

Au

Do you think both these bottles contain gold?

*Can we see patterns in chemical

formulas and their compounds?

All matter in the universe either is an element ,or is made of some combination of elements.

Element: A unique substance that cannot be broken down into simpler substances through chemical processes. Elements serve as the building materials of all matter.

There are approximately 118 known elements

which are organized in the Periodic Table

based on some of their properties.

An element is represented by a symbol.

The first letter of an element’s symbol is always

uppercase and if there is a second letter it is

always lowercase.

Compound: A pure substance that is a chemical combination of two or more elements in a fixed ratio.

Compounds are

represented by

chemical formulas

which are a

combination of

symbols and

subscripts that indicate

the number and types

of elements in the

compound.

*Chemical formula for copper sulfate

Symbol for sulfur

Symbol for oxygen

Subscript for # of

oxygen atoms

Symbol for copper

CuSO4(aq)

Chemical formulas indicate the number and types of

elements in the compound.

Compounds (therefore chemical formulas) are “fixed”.

Some common groupings of elements have their own specific names.

OH hydroxide

NO3 nitrate

SO4 sulfate

SO3 sulfite

Substances come in different physical forms, called phases.

In chemistry it is common to include the phase of the compound with its formula.

Phase: The physical form a substance is in, such as solid, liquid, or gas. Phase is greatly influenced by temperature.

Aqueous: A substance is aqueous when it is dissolved in water.

Remember: “liquid” is a phase

Sodium nitrate NaNO3(aq)

Copper II nitrate Cu(NO3) 2 (s)

Nitric acid HNO3(aq)

water H2O(l)

copper Cu(s)

Sodium hydroxide NaOH(s)

Sodium hydroxide NaOH(aq)

*summary * What do chemical names and symbols tell you

about matter?

* Chemical symbols represent the elements. Each element has either a one- or two-letter symbol. The first letter is always uppercase; the second letter is always lowercase.

* The chemical formula of a substance indicates what elements are in it as well as the relative amounts of each element in that substance.

* The symbols (s), (l), (g), and (aq) indicate the physical form or phase of a substance and whether it is dissolved in water.

*Lesson 7: Now You See It

* The Copper Cycle

*Check-in

* Imagine that you find a vial labeled Na2SO4(aq). What does the label tell you about what is in this vial?

* Compare and contrast “element” and “compound”

* What is the difference between (l) and (aq)?

*After this lesson You will be able

to:

* follow a lab procedure safely

* describe a chemical change or chemical

reaction

*Key Question

* What happens to matter when it is changed?

Read the lab procedure - pay close attention

to the safety precautions for today’s lab.

use

fume

hood

*Prepare for the Lab

During the lab, follow these safety guidelines:

* Wear your safety goggles at all times.

* Be very careful when handling chemicals. If any gets on your skin, wash the area immediately with water and inform your teacher.

* Use the fume hood when adding the nitric acid to the copper; do not breathe in any of the gas.

* When using the hot plate, set it at a medium setting. Be careful not to splash when stirring the chemicals.

* Remove the beaker from the hot plate with beaker tongs.

*Lab analysis

You could see copper only in the first and

last steps of the lab. Where do you think the

copper was the rest of the time? Be specific.

*Chemical changes

(reactions)

The copper cycle lab illustrates the process

of chemical reactions. You caused the

copper to undergo chemical changes.

Evidence of a chemical change is

the formation of “new”

substances.

An iron nail is left in contact with water and air and

forms a reddish brown coating (rust).

a. Is this a chemical change? What’s the evidence?

b. Is rust an element, a compound or a mixture?

Explain

c. How could you gather evidence to answer b above?

When a chemical change/reaction occurs, a

new substance is formed with different

chemical properties than the original

substance.

Clues of chemical changes:

• gas is formed

• precipitate is formed

• color change**

• light/sound

Chemical changes do not change the

underlying elements.

*A familiar example

NaHCO3(s) + CH3COOH(l) →

CO2(g) + H2O(l) + Na+(aq) + CH3COO-(aq)

*Lesson 8: What Goes Around

Comes Around

* Conservation of Matter

What do you think happened to the

copper powder in the copper cycle

experiment when it was mixed with the

nitric acid?

*Key Question

What happens to elements in a chemical change?

youtube

You could prove that copper was not

destroyed by measuring the mass of the

copper powder at the beginning and at

the end of the experiment.

•.

Law of conservation of mass: The law

states that mass cannot be gained or lost in

a chemical reaction–matter cannot be

created or destroyed, but it can change form.

Why might it be difficult to demonstrate the

Law of Conservation of Mass with your

copper cycle lab?

Chemical reaction:

Cool chemical reactions

reactants products

Chemical reactions occur when substances combine or

break apart. The starting substances are called reactants.

The ending substances are called the products.

In a chemical reaction, the end products have

different properties than each of the individual

reactants.

Chemical equations are a way to write out a

chemical reaction. They can be written in word form,

or in symbol form.

*an example:

Golden rain

potassium iodide + lead nitrate →

lead iodide + potassium nitrate

KI(aq) + Pb(NO3)2(aq) → PbI2 (s) + KNO3(aq)

*4 basic Types of chemical

reactions

demonstrations

*text notes

No matter what was done to the copper, it was

not broken down any further.

The observations we have made in the copper

cycle lab provide further evidence that the

golden penny is not gold.

*Lesson summary

What happens to elements in a chemical

change?

* Elemental copper can be transformed through

chemical reactions and then recovered.

* We can represent elements with symbols and keep

track of them during chemical reactions.

* Elements combine and recombine but are not

created or destroyed in chemical reactions.

Video summary

*Balancing chemical

equations

* remember: Compounds are represented

by chemical (molecular) formulas

2 Cl Cl2 2Cl2

• Molecules may also have brackets to

indicate numbers of atoms. E.g. Ca(OH)2

O H

O H

Ca

• Notice that the OH is a group

• The 2 refers to both H and O

a) NaOH

b) Ca(OH)2

c) 3Ca(OH)2

Na = 1, O = 1, H = 1

Ca = 1, O = 2, H = 2

Ca = 3, O = 6, H = 6

How many of each atom are in the

following?

*Law of conservation of

mass

Mass is not created or destroyed during a chemical reaction or physical change – but it can change form.

Must have same number of atoms before and

after the reaction.

When this condition is met, you have a

balanced equation.

Fe + O2 Fe2O3

Coefficients are written in front of the

formulas to satisfy the law of conservation

of mass.

2 3 4

*Balancing equations: MgO

Magnesium + Oxygen magnesium oxide

Mg + O2 MgO

O Mg O + Mg O

• However, this is not balanced

Left: Mg = 1, O = 2

Right: Mg = 1, O = 1

*Balance equations by

“inspection”

Mg + O2 MgO

2Mg + O2 2MgO is correct Mg + ½O2 MgO is incorrect

4Mg + 2O2 4MgO is incorrect

a) Mg + HCl MgCl2 + H2

b) Ca + N2 Ca3N2

c) NH4NO3 N2O + H2O

d) BiCl3 + H2S Bi2S3 + HCl

e) C4H10 + 13O2 8CO2 + 10H2O

f) 6 O2 + C6H12O6 CO2 + H2O

g) NO2 + H2O HNO3 + NO

h) Cr2(SO4)3+ NaOH Cr(OH)3+ Na2SO4

i) Al4C3 + H2O CH4 + Al(OH)3

Balance these skeleton equations: 2

3

3

3

2

2

2

2

3

3

2

6

6 6

6

12 4

*Lesson 9: Create A

Table

Properties of the Elements

*Check-in

Sodium chloride, NaCl (aq), is added to silver nitrate, AgNO3 (aq), resulting in NaNO3 (aq) and a white solid.

*Identify the white solid from the list below. Explain your choice.

A. AgCl (s) B. AgCl (aq)

*C. AgNO3(s) D. NaCl (s)

Chemical reaction of molten

NaCl

*Key Question

* Key Question:

How is the periodic table organized?

*You will be able to:

* describe how the organization of the periodic

table is based on reactivity and atomic mass

* predict the characteristics of a missing element

on the periodic table based on its position in the

table

* Work in groups of three with one set of Create a

Table cards for each group.

Aristotle

*Early Greeks

* 400 B.C. - Democritus thought matter could not

be divided indefinitely.

• 350 B.C - Aristotle modified an earlier theory that

matter was made of four “elements”: earth, fire,

water, air.

Democritus

Aristotle was wrong. However, his theory

persisted for 2000 years.

fire

air

water

earth

This led to the coining of the name “atom”.

*Dmitri Mendeleev

Early chemists understood

the importance of

relationships among chem.

and phys. properties of

elements.

*Mendeleyev organized his periodic table based on the

properties of the elements, such as reactivity and atomic

mass.

*Mendeleyev’s arrangement of the elements helped predict

the existence and properties of as-yet-undiscovered

elements.

What is reactivity?

Reactivity is a property that describes whether an

element or compound will chemically combine

with other substances to form compounds and

also describes the speed of a reaction.

Reactivity

of the Alkali

metals

Reactivity

information is

included on the

Create a Table

cards.

*A Closer Look at

Chemical

Reactions Reaction Lab

Bill Nye

*Reactivity is an important

chemical property of elements

Can we predict how different elements will

react?

Position in the

periodic table is

important.

Atomic Mass: The mass of a single

atom (or isotope) of an element.

Each element has an average atomic mass

that is expressed as a decimal number.

These are the

numbers that appear

on the Create a Table

cards.

*Examining patterns

Based on your table:

• What approach did you choose as your

main basis of organization?

• Did you have to abandon any

characteristics and pick different ones?

• Why didn’t everyone choose the same

method?

* examining patterns cont.

• What were some patterns you discovered in

your arrangement?

• Where did you put H and He? What was your

reasoning?

• Did you have any cards that didn’t fit your

pattern? Or were difficult to place?

Which card did you choose?

Where did you place it?

Reacts

slowly with

oxygen

Found in

GeH4 gas

Moderately

soft, silvery

solid,

metalloid

* examining

patterns cont

• Did you discover any new characteristics or

patterns in this activity?

• How do you think this organization of the

elements might be useful to chemists?

• How did Mendeleyev predict

new elements before they

were discovered?

*Patterns in the Periodic table

The Periodic Table contains tremendous

amounts of information about the elements.

Knowing the precise location of an element in

the Periodic table can help predict many of its

characteristics.

Mendeleyev organized his periodic table

based on the properties of the elements, such

as reactivity and atomic mass.

Mendeleyev’s arrangement of the elements

helped predict the existence and properties of

as-yet-undiscovered elements.

*summary

How is the periodic table organized? * Mendeleyev organized his periodic table based on

the properties of the elements, specifically, reactivity and atomic mass.

* Elements in each column of the periodic table have similar properties.

* Reactivity describes whether an element will chemically combine with other common substances and also describes the speed of the reaction.

* Mendeleyev’s arrangement of the elements helped predict the existence of undiscovered elements.

*Lesson 10: Breaking the

Code The Periodic Table

*Check-in

Which of these elements would be grouped

together on the periodic table? Explain your

thinking.

cadmium

Cd

moderately soft,

silvery, solid, metal

reacts very slowly

with water found in CdCl2(s)

zinc

Zn

moderately hard,

silvery, solid, metal

reacts very slowly

with water found in ZnCl2(s)

iodine

I

purple, solid,

nonmetal

reacts slowly with

metals found in ICl(s)

mercury

Hg silvery, liquid, metal

does not react

with water found in HgCl2(s)

Where would you place silver (Ag) and

gold (Au) in the periodic table you

created with your cards?

*Key Question

What information does the periodic table reveal about the

elements?

*You will be able to:

* use the periodic table to identify elements that are metals, nonmetals, metalloids, alkali metals, alkaline earth metals, transition elements, halogens, noble gasses, lanthanides, and actinides

* describe the general properties of elements, that are periodic in nature

* predict the general properties of an element based on its location on the periodic table and identify elements that will exhibit similar chemical behavior

In groups of four, sort the Create a Table cards

using the patterns you discovered in Lesson 9:

Create a Table.

Now open up the table to accommodate for more

elements.

*Evolution of the Periodic Table

Add Mendeleyev’s remaining elements.

Elements are arranged in the Periodic table based on their atomic number

the atomic number identifies the element

The atomic

number is equal

to the number of

protons in the

nucleus of the

element.

Important information about the

elements are shown:

Grouping elements shows a recurring,

periodic, predictable pattern.

Rows are called “periods”

Columns are called

“groups” or “families”

Elemental properties in periods increase/decrease as you move across the periodic table. The patterns in Periods repeat periodically over and over again.

*Periodic Table vocabulary

The Families of the periodic table

All elements in a family exhibit similar properties.

Lanthanides and actinides

If you examine the atomic numbers of these elements,

you’ll see they belong in the sixth and seventh

periods. They are “pulled out” and typically shown

below the Periodic Table merely for convenience.

Their periodic trends are consistent with the rest of the

table.

The elements of the periodic table can be broken into three

different groups: metals, metalloids (or semi-metals) and

nonmetals.

Alkali metals: The elements in Group 1A.

Alkaline earth metals: The elements in Group 2A.

Halogens: The elements in Group 7A.

Noble gases: The elements in Group 8A. They are called

“noble” gases because they are not reactive.

Periodic Families (Groups)

*The metals

Properties of Metals

• solid at room temperature (with

the exception of mercury)

• usually shiny

• high melting point

• good conductor of heat

• good conductor of electricity

• malleable – able to be pounded

into sheets

• ductile – can be pulled into wire

• high density (exceptions:

lithium, potassium and sodium)

• corrodes in air or seawater

• loses electrons in

reactions

alkali metal reactions.html

Specific metal families:

• they react with water to form hydroxide

ions, creating basic solutions (pH>7),

• among the most reactive metals

• Lowest electronegativity of all element

families.

• They produce bright, colorful flames

making them very useful in fireworks.

• shiny.

• silvery-white.

• somewhat reactive

metals at standard

temperature and

pressure.

• readily lose their two

outermost electrons to

form cations with a 2+

charge.

• low densities.

• low melting points.

• low boiling points.

Alkali earth

metals

Specific metal families:

*The nonmetals

Properties of nonmetals

• dull, not shiny

• poor conductor of heat

• poor conductor of electricity

• not malleable or ductile,

usually brittle

• lower density (when

compared to metals)

• lower melting point and

boiling points (when

compared to metals)

• gain electrons in

reactions

nonmetals

Many are gas at r.t. Solids tend to be brittle Low conductivity Poor conductors of heat

halogens

Noble gases

Gas at r.t. Non-reactive – have stable octets

metalloids

Characteristics of both metals and nonmetals

ALL are solid at r.t.

Semiconductors

Can gain and loose electrons in reactions

There is no standard definition of a metalloid, nor is there complete

agreement as to which elements are appropriately classified as such.

*More trends in the

Periodic Table

Elemental phases

Most elements are

solid at room

temperature

Hg

Ga

Br

Once the

elements are

arranged

according to

atomic number

and general

properties, many

other patterns

emerge.

There are

horizontal,

vertical and

diagonal!

patterns.

*Summary

*What information does the periodic table reveal about the elements?

* Patterns repeat on the periodic table. The table is organized so elements in each column of the periodic table have similar properties.

* The periodic table lists the name, symbol, and average atomic mass of each element.

* Several groups of elements and some periods have specific names, such as halogens or noble gasses.

* Metals are in the center and left, and nonmetals are at the top right; elements near the dividing line are considered metalloids.

*Compounds can be

separated based on their

size and charge.