Review Periodic Table Bill Nye The Science Guy Elements & electrons 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 ______ ________. Atomic Mass - mass of average atom Atomic Number - number of protons Ion Charge - electric charge that forms when an atom gains or loses electrons See page 53

Metals: left Non-metal: right Metalloids Periodic Table

Metals, Non-metals, Metalloids Due to Mendeleev’s organization, interesting patterns are created, such as the groups: metals, non-metals and metalloids. See page 55

Periods and Families Each horizontal row in the periodic table is a period Vertical columns form groups or chemical families 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 See pages 56 - 57

Physical Change Physical 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 are changes matter undergoes when it becomes new or different matter. To identify a chemical change look for signs such as ______________

Chemical changes A compound is composed of at least TWO elements. How are they made?

Bill Nye

Video question sheet

Bill Nye Chemical Rxns Video …chemical reactions Stomach grumbling, metal rusting, Twice as much. H20 – two hydrogen, one oxygen The electrons are recombining with other electrons Energy – can be given off in heat, sound, light.. Chemical bonds Oxygen and wood/paper make carbon dioxide, water, Vinegar and baking soda – makes carbon dioxide gas 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 Electrons can move….but for each element the Number of electrons = N Number of protons ATOMIC For Titanium: Protons= 22 Electron = THE SAME=22 Neutrons= 48-22= 26

Lets Practice: Element Symbol Protons Electrons Neutrons Sodium

Lets Practice: Oxygen 34 Pb Chlorine Element Symbol Protons Electrons Neutrons Oxygen 34 Pb Chlorine

Oxygen Selenium Lead Chlorine Element Symbol Protons Electrons Neutrons Oxygen O 8 Selenium Se 34 45 Lead Pb 82 126 Chlorine Cl 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 See page 64 - 65 (c) McGraw Hill Ryerson 2007

Bohr model patterns Chemical families on the periodic table have the same number 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 Stability Noble gases are very unreactive because their atoms have 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 stability of 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+) and 10 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. - + + -

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…. Li Lithium 3 7 How to draw a Lithium atom First, look at the Periodic Table How to draw a Lithium atom 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 Li Lithium 7

So let’s try it…. Li Lithium Protons = 3 3 7 Neutrons = 4 (7-3=4) - + Electrons = 3 2 in the 1st shell, 1 in the 2nd shell Neutrons = 4 (7-3=4)

Lewis Dot Structure O • • • • • • 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 • • • • •