Today:

Review Periodic Table

Bill Nye The Science Guy

Elements & electrons

This week: elements & electrons

Reaction lab – Due Tuesday

Marks: 10 observations/questions

25 for your conclusion

TEST– Thursday Graphing

States of Matter

Atomic history

Periodic Table

I will be looking at your lab’s conclusion

Conclusions must be based on your RESULTS

A black colour, thick smoke and a strong odor were observed when bread was toasted for 30 minutes. As the colour remained when cooled, a new substance was created and a chemical reaction observed.

Elements

Matter is anything that takes up space and has mass.

Elements and compounds are pure substances:

An element is ONE TYPE of atom and cannot be broken down or separated into simpler substances.

Periodic Table

• Origin of the periodic table

In 1867, Dimitri Mendeleev found patterns in the elements and organized them into table

The resulting table had holes

for elements not yet discovered

Periodic Table

The Periodic Table provides information on the physical and chemical properties of elements and ______ ________.

See page 53

Atomic Mass - mass of average atom

Atomic Number - number of protons

Ion Charge - electric charge that forms when an atom gains or loses electrons

Periodic TableMetals: left

Non-metal: right

Metalloids

Metals, Non-metals, MetalloidsDue to Mendeleev’s organization, interesting patterns are created, such as the groups: metals, non-metals and metalloids.

See page 55

Periods and FamiliesEach horizontal row in the periodic table is a period

Vertical columns form groups or chemical families

See pages 56 - 57

Alkali metals - highly reactive group 1

Alkaline earth metals - group 2, burn in air if heated Halogens - group 17, highly reactive non-metals

Noble gases - group 18, stable and unreactive non-metals

Physical ChangePhysical changes occur when matter changes in energy or appearance but not its chemical nature.

Physical property changes could include a change in state (ice melting), or size (cutting paper)

But NO new substances are formed

Chemical Change

Chemical changes

A compound is composed of at least TWO elements.

•How are they made?

Bill Nye

Video question sheet

Bill Nye Chemical Rxns Video1. …chemical reactions

2. Stomach grumbling, metal rusting,

3. Twice as much. H20 – two hydrogen, one oxygen

4. The electrons are recombining with other electrons

5. Energy – can be given off in heat, sound, light..

6. Chemical bonds

7. Oxygen and wood/paper make carbon dioxide, water,

8. Vinegar and baking soda – makes carbon dioxide gas

9. Metals and salts – copper burns blue

Electrons & chemical bonds

Elements with similar electron structure have similar properties.

Protons, Electrons and Neutrons

We ALL must be able to calculate the follow:

Number of Protons= ATOMIC NUMBER

Number of Neutrons=(Atomic mass – atomic number)

Number of electrons = can change, electrons

move!

Protons, Electrons and Neutons

Lets Practice:Element Symbol Protons Electrons Neutrons

Sodium

Lets Practice:Element Symbol Protons Electrons Neutrons

Oxygen

34

Pb

Chlorine

Element Symbol Protons Electrons Neutrons

Oxygen O 8 8 8

Selenium

Se 34 34 45

Lead Pb 82 82 126

Chlorine Cl 17 17 19

Tomorrow: Borh Diagrams

Tonight: Review worksheet

Tuesday

• Lab- conclusion

• Where did elements come from video pbs

• Borh diagrams

Periodic Table and Atomic Theory

Elements with similar properties have similar electron arrangements

Bohr models show electron arrangement in shells

(c) McGraw Hill Ryerson 2007

See page 64 - 65

Bohr model patternsChemical families on the periodic table have the samenumber of valence electrons

Elements in the same period have the same number of shells

Period number indicates the number of electron shells

See page 66

Atom StabilityNoble gases are very unreactive because their atomshave filled valence shells. Filled shells make atoms stable.Atoms with filled shells do not easily trade or share electrons.

Other atoms gain or lose electrons in order to achieve the stabilityof noble gases. Gaining or losing electrons makes atoms into ions.

Metals lose electrons to form positive ions

Non-metals gain electrons to form negative ions

Ions have a similar electron arrangement to the nearest noble gas

Example: Sodium ion (Na+) has 11 protons (11+) and10 electrons (10-) for a total charge of 1+

See pages 66 - 67

Elements & Atoms

An atom refresher

• Matter is anything that takes up space and has mass.

• All matter is made of atoms

• Atoms are the building blocks of matter, sort of how bricks are the building blocks of houses.

An atom refresher• An atom has three parts:

• Proton = positive

• Neutron = no charge

• Electron = negative

• The proton & neutron are found in the center of the atom, a place called the nucleus.

• The electrons orbit the nucleus on the electron cloud

Picture from http://education.jlab.org/qa/atom_model_03.gif

What are elements?• Elements are the

alphabet to the language of molecules.

• To make molecules, you must have elements.

• Elements are made of atoms. While the atoms may have different weights and organization, they are all built in the same way.

Bohr Model• The Bohr Model shows

all of the particles in the atom.

• In the center is circles. Each circle represents a single neutron or proton. Protons should have a plus or P written on them. Neutrons should be blank or have an N.

• In a circle around the nucleus are the electrons. Electrons should have a minus sign or an e.

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Electrons have special rules….

• You can’t just shove all of the electrons into the first orbit of an electron.

• Electrons live in something called shells or energy levels.

• Only so many can be in any certain shell.

Electrons have special rules….

• You can’t just shove all of the electrons into the first orbit of an electron.

• Electrons live in something called shells or energy levels.

• Only so many can be in any certain shell.

• The electrons in the outer most shell of any element are called valance electrons.

So let’s try it….• How to draw a Lithium atom

• First, look at the Periodic Table

• Second, determine the number of protons (Look @ the atomic number)

• Then determine the number of neutrons (Atomic mass – atomic number)

• Then determine the number of electrons (Look @ the atomic number)

3

LiLithium

7

So let’s try it….3

LiLithium

7

++

++++

Protons = 3

Neutrons = 4

(7-3=4)

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Electrons = 3 Electrons = 3

2 in the 12 in the 1stst shell, 1 in the 2 shell, 1 in the 2ndnd shell shell

Lewis Dot Structure• The Lewis Dot

Structure is a bit different from the Bohr model.

• It only shows the element symbol and it’s outer most electron shell.

O• ••• •

•

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++ ++

++

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