CHAPTER 5 – PROPERTIES AND CHANGES
5.1 EXPLORING THE NATURE OF MATTER
THE PARTICLE THEORY:
-ALL MATTER IS MADE UP OF EXTREMELY TINY PARTICLES
-EACH PURE SUBSTANCE HAS ITS OWN KIND OF PARTICLE WHICH IS
DIFFERENT FROM OTHER SUBSTANCES
-PARTICLES ATTRACT EACH OTHER
-PARTICLES ARE ALWAYS MOVING
-PARTICLES MOVE FASTER AT HIGHER TEMPERATURES
-MATTER IS CLASSIFIED INTO:SOLID, LIQUID, GAS. (SEE FIGURE 5.1)
-WE CAN ALSO CLASSIFY BASED ON PROPERTIES. IF SO, WE USE
TERMS LIKE: HETEROGENEOUS (DIFFERENT), HOMOGENEOUS (SAME).
-FINALLY, WE CAN CLASSIFY ACCORDING TO ITS COMPOSITION. IF SO,
WE USE TERMS LIKE: MIXTURE OR PURE SUBSTANCE.
- (SEE FIGURE 5.2)
CHANGES IN MATTER
-MATTER HAS PROPERTIES THAT HELP TO IDENTIFY THE SUBSTANCE
-WHEN A SUBSTANCE CHANGES IT EITHER GOES THROUGH PHYSICAL
CHANGES OR CHEMICAL CHANGES.
-IN PHYSICAL CHANGES, NO NEW SUBSTANCE IS FORMED AND IT IS
EASILY REVERSABLE. (SEE FIGURE 5.3)
-IN CHEMICAL CHANGES, AT LEAST ONE NEW SUBSTANCE IS CREATED
WITH NEW PROPERTIES FORMED. IT IS ALSO VERY DIFFICULT TO
REVERSE A CHEMICAL CHANGE. (SEE FIGURE 5.4)
PROPERTIES: PHYSICAL OR CHEMICAL
-PHYSICAL –PROPERTY THAT CAN BE OBSERVED OR MEASURED
WITHOUT FORMING A NEW SUBSTANCE. (COLOR, DENSITY, LUSTER)
-CHEMICAL – ANY PROPERTY THAT DESCRIBES HOW A SUBSTANCE
REACTS WITH ANOTHER SUBSTANCE WHEN FORMING A NEW
SUBSTANCE. (COMBUSTIBILITY)
-PHYSICAL CHANGES ARE BROKEN INTO QUALITATIVE AND
QUANTITATIVE CHARACTERISTICS. (SEE TABLE 5.2)
-SEE FIGURE 5.6 TO IDENTIFY 5 SEPARATE PHYSICAL PROPERTIES OF
DIFFERENT ELEMENTS.
-INVESTIGATION 5-A ON PAGE 160-163. DO PARTS 1,2,3,5,6,7,8.
DENSITY BY THE NUMBERS
-DENSITY IS THE AMOUNT OF MATTER THAT OCCUPIES A CERTAIN
SPACE.
IT IS THE MASS PER UNIT VOLUME OF A SUBSTANCE.
-DENSITY CAN HELP US IDENTIFY CERTAIN TYPES OF SUBSTANCES.
-DENSITY, MASS, AND VOLUME CAN BE CALCULATED BY USING THE
FOLLOWING FORMULAS:
DENSITY = MASS
VOLUME
MASS = VOLUME x DENSITY
VOLUME = MASS
DENSITY
OR
OR
OR
D=m
V
m=VxD
V=m
D
CHEMICAL CHANGE REVIEW
-IF 2 OR MORE OF THE FOLLOWING OBSERVATIONS TAKE PLACE,
THEN A CHEMICAL CHANGE HAS OCCURRED:
1. HEAT IS ABSORBED OR PRODUCED
2. THE STARTING MATERIAL IS USED UP
3. A NEW COLOUR APPEARS
4. A STARTING COLOUR DISAPPEARS
5. A MATERIAL WITH NEW PROPERTIES FORMS
6. GAS BUBBLES FORM IN A LIQUID
7. GRAINS OF SOLID PRECIPITATE FORM IN A LIQUID
-DO CYU 5.1 ON PAGE 169 #1-3
5.2 MIXTURES
-ONE TYPE OF MIXTURE IS CALLED A SOLUTION. A SOLUTION IS MADE
OF TWO DIFFERENT PARTS. THE SOLUTE IS THE LEAST ABUNDANT
PART OF THE SOLUTION WHILE THE SOLVENT IS THE MOST
ABUNDANT PART OF THE SOLUTION. (SEE FIGURE 5.10 A-C)
-EVERY SOLUTION RETAINS SOME PROPERTIES OF BOTH THE SOLUTE
AND SOLVENT.
-WHEN MAKING A SOLUTION YOU CAN HAVE EITHER A PHYSICAL OR
CHEMICAL CHANGE AND IT WILL BE HOMOGENEOUS IN APPEARANCE.
-WHEN A MIXTURE IS HETEROGENEOUS IN APPEARANCE THEN IT IS A
MECHANICAL MIXTURE AND NOT A SOLUTION. (SEE FIGURE 5.11)
-WHEN ONE OR MORE METALS ARE COMBINED TOGETHER TO FORM A
HOMOGENEOUS MIXTURE IT IS CALLED AN ALLOY. WHEN A NEW
METAL IS COMBINED TO A PURE SUBSTANCE, IT CHANGES THE
PROPERTIES OF THE PURE SUBSTANCE. EXAMPLE: IRON ALONE
RUSTS EASILY. IRON, CARBON, NICKEL, AND CHROMIUM FORM
STAINLESS STEEL. ANOTHER EXAMPLE IS GOLD AND COPPER. (SEE
FIGURE 5.12)
-SUSPENSIONS AND COLLOIDS ARE 2 OTHER TYPES OF MECHANICAL
MIXTURES. YOU CAN SEE THE LARGER PARTICLES OF A SUSPENSION
EASILY, AND THEY SETTLE OUT OVER TIME IF UNDISTURBED. IN
COLLOIDS THE PARTICLES ARE SMALL ENOUGH THAT GRAVITY WILL
NOT CAUSE THEM TO SEPARATE.
-THE TYNDALL EFFECT IS THE SCATTERING OF LIGHT BY COLLOID
PARTICLES. IT ALLOWS US TO TELL IF A SUBSTANCE IS A COLLOID OR
A SOLUTION.
-ACTIVITY “KEEP IT TOGETHER” ON PAGE 173. CAREFULLY GO
THROUGH THE 4 STEPS AND COMPLETE THE “WHAT DID YOU
DISCOVER” QUESTIONS.
-DO CYU 5.2 ON PAGE 174 #1-3
5.3 COMPOUNDS AND ELEMENTS
-COMPOUNDS ARE PURE SUBSTANCES THAT ARE MADE UP OF TWO OR
MORE ELEMENTS CHEMICALLY COMBINED TOGETHER.
-IN EARLIER TIMES, PHILOSOPHERS THOUGHT ABOUT THE
PROPERTIES OF MATTER. THEY DIDN’T BELIEVE IN
EXPERIMENTATION, BUT RATHER JUST THINKING ABOUT POSSIBLE
OUTCOMES. THE FIRST PEOPLE THAT EXPERIMENTED WITH MATTER
WERE CALLED ALCHEMISTS. ALCHEMISTS DID MANY EXPERIMENTS
AND KEPT THEIR WORK VERY SECRET.
-IN 1620, THE SCIENTIST NAMED FRANCIS BACON WROTE A BOOK THAT
ARGUED THAT SCIENCE SHOULD BE BASED ON EXPERIMENTAL
EVIDENCE RATHER THAN JUST PHILOSOPHY ALONE.
-SHORTLY AFTER BACON, ROBERT BOYLE INTRODUCED SKEPTICISM
ABOUT THE EARLY PHILOSOPHERS IDEAS. HE TALKED ABOUT MANY
ELEMENTS THAT COULD FORM COMPOUNDS WHEN COMBINED. THESE
IDEAS LEAD TO A NEW APPROACH IN EXPERIMENTAL SCIENCE.
-ONE EXPERIMENT THAT IS USED TO DECOMPOSE COMPOUNDS IS
CALLED ELECTROLYSIS. IN THIS PROCESS AN ELECTRIC CURRENT IS
RUN THROUGH A SUBSTANCE AND BREAKS IT DOWN INTO SEPARATE
PURE SUBSTANCES. WE CAN ISOLATE HYDROGEN AND OXYGEN FROM
WATER BY THIS METHOD.
-ANTOINE LAVOISIER WAS THE FIRST TO USE THE METHOD OF
ELECTROLYSIS. HE WAS VERY CAREFUL IN MEASUREING THE MASS
OF EACH SUBSTANCE INVOLVED IN THE EXPERIMENT. THIS
INFORMATION WAS USED BY JOSEPH PROUST IN LATER EXPERIMENTS.
-PROUST STARTED TO NOTICE PATTERNS IN DECOMPOSITION. THIS
DISCOVERY LED TO THE LAW OF DEFINITE PROPORTIONS. FOR
EXAMPLE, PURE WATER ALWAYS CONTAINS 11% HYDROGEN AND 89%
OXYGEN BY MASS. SINCE IT ALWAYS HAS THE SAME COMPOSITION IT
ALSO HAS THE SAME PROPERTIES. THE MELTING AND BOILING POINT
OF PURE WATER IS ALWAYS 0 AND 100 DEGREES CELCIUS
RESPECTIVELY.
-INVESTIGATION 5-B ON PAGE 177. TEACHER DEMO.
-DO CYU 5.3 ON PAGE 182 #1-3
5.4 ATOMIC THEORY: EXPLAINING CHEMICAL FACTS AND LAWS
-DALTON’S ATOMIC THEORY HELPS TO EXPLAIN CHEMICAL FACTS
AND LAWS.
1. ALL MATTER IS MADE UP OF SMALL PARTICLES CALLED ATOMS.
2. ATOMS CANNOT BE CREATED, DESTROYED, OR DIVIDED INTO
SMALLER PARTICLES.
3. ALL ATOMS OF THE SAME ELEMENT ARE IDENTICAL IN MASS AND
SIZE, BUT THEY ARE DIFFERENT IN MASS AND SIZE FROM THE ATOMS
OF OTHER ELEMENTS.
4. COMPOUNDS ARE CREATED WHEN ATOMS OF DIFFERENT ELEMENTS
LINK TOGETHER IN DEFINITE PROPORTIONS.
-AN ELEMENT IS A PURE SUBSTANCE MADE UP OF ONE TYPE OF
PARTICLE, OR ATOM. IT HAS ITS OWN DISTINCT PROPERTIES AND
CANNOT BE BROKEN DOWN INTO SIMPLER SUBSTANCES BY CHEMICAL
MEANS.
-A SCIENTIFIC LAW DESCRIBES AND SUMMARIZES SOMETHING THAT
HAPPENS.
-A SCIENTIFIC THEORY IS AN IMAGINATIVE WAY TO EXPLAIN WHY
SOMETHING HAPPENS.
-DALTON USED THE PROCESS OF ELECTROLYSIS TO ILLUSTRATE THAT
COMPOUNDS OCCUR IN A FIXED MASS RATIO. WHEN WATER IS
DECOMPOSED BY ELECTROLYSIS THE MASS OF THE OXYGEN IS 89%
AND HYDROGEN IS 11%. THIS LED TO THE TERM; MASS NUMBER.
-DO CYU 5.4 ON PAGE 186 #1-2
-DO CHAPTER AT A GLANCE QUESTIONS (ALL) ON PAGE 187
-DO CHAPTER 5 REVIEW ON PAGE 188 #1-15
CHAPTER 6 – MEET THE ELEMENTS
6.1 SYMBOLS FOR THE ELEMENTS
-WE USE CHEMICAL SYMBOLS FOR IDENTIFYING ELEMENTS AS A
SHORTHAND WAY OF EXPRESSING THEM. JONS BERZELIUS WAS THE
FIRST TO PROPOSE SUCH AN IDEA BY USING CHEMICAL SYMBOLS.
NOW, THIS SYSTEM IS USED THROUGHOUT THE WORLD. (SEE TABLE
6.1)
-COMPOUNDS ARE FORMED WHEN TWO ELEMENTS JOIN TOGETHER.
SO WHEN WE WRITE A CHEMICAL FORMULA WE COMBINE THE
CHEMICAL SYMBOLS OF THE ELEMENTS INVOLVED. H2O IS A
CHEMICAL SYMBOL THAT CONTAINS THE ELEMENTS HYDROGEN AND
OXYGEN. A MOLECULE IS THE SMALLEST INDEPENDENT UNIT OF A
COMPOUND. H20 IS ONE MOLECULE OF WATER.
-IN H2O THE H = HYDROGEN, THE LITTLE 2 TELLS US THAT THERE ARE
2 HYDROGEN ATOMS PRESENT, AND THE O = OXYGEN. BECAUSE
THERE IS NO NUMBER BEHIND THE OXYGEN IT MEANS THERE IS ONLY
1 THERE.
-FLAME TEST DEMO BY TEACHER.
-INVESTIGATION 6-A ON PAGE 195. FILL IN CHARTS FOR PART 1+3. DO
PART 2 ON LOOSELEAF.
PART #1:
NAME OF
COMPOUND
WATER
FORMULA OF
COMPOUND
H2O
CARBON DIOXIDE
CO2
PROPANE
C3H8
GLUCOSE
C6H12O6
ELEMENTS
PRESENT
HYDROGEN,
OXYGEN
HOW MANY ATOMS
OF EACH
2 ATOMS H,
1 ATOM O
PART #3
NAME OF GAS
WATER VAPOUR
COMPOUND OR
ELEMENT
COMPOUND
MADE OF
MOLECULES?
CARBON
DIOXIDE
-DO CYU 6.1 ON PAGE 197 #1-6
ATOMS PER
MOLECULE
CO2
OXYGEN
NITROGEN
FORMULA
2
YES
6.2 ELEMENTS ON PLANET EARTH
-THE ATMOSPHERE IS THE GASEOUS AREA SURROUNDING THE
PLANET. IT IS COMPOSED OF NITROGEN (78%), OXYGEN (21%), ARGON
(1%), AND SOME OTHER TRACE GASES.
-THREE OF THESE GASES UDERGO CYLES IN OUR ATMOSPHERE.
LIVING THINGS USE OXYGEN FOR CELLULAR RESPIRATION. PLANTS
USE CARBON DIOXIDE FOR PHOTOSYNTHESIS. NITROGEN IS USED IN
THE BUILDING OF PROTIENS.
-THE HYDROSPHERE IS THE NEARLY CONTINUOUS LAYER OF WATER
LYING ON OR JUST UNDER THE EARTH’S CRUST. THIS INCLUDES THE
ICE CAPS AT THE POLAR REGIONS.
-PURE WATER MOLECULES ARE MADE OF TWO HYDROGEN ATOMS
AND ONE OXYGEN ATOM. WATER IN NATURE HAS SUBSTANCES
DISSOLVED IN IT. FISH NEED DISSOLVED OXYGEN FOR RESPIRATION
WHILE UNDERWATER PLANTS NEED DISSOLVED CARBON DIOXIDE FOR
PHOTOSYNTHESIS.
-THE LITHOSPHERE IS THE SOLID MATERIAL THAT MAKES UP THE
EARTH’S CRUST. SEE FIGURE 6.9 SOME ELEMENTS DO NOT REACT
WITH OTHER ELEMENTS WHILE MOST OTHERS COMBINE TO FORM
COMPOUNDS. AN ELEMENT’S REACTIVITY IS ITS ABILITY TO COMBINE
WITH ANOTHER ELEMENT.
-ELEMENTS ON THE PERIODIC TABLE ARE DIVIDED INTO 3 MAJOR
GROUPINGS.
-1. METALS ARE THE LARGEST ELEMENT GROUPING. THEY CONDUCT
ELECTRICITY AND HEAT WELL. THEY CAN ALSO BE HAMMERED INTO
SHEETS (MALLEABILITY), OR STRETCHED INTO WIRES (DUCTILITY).
METALS ARE SHINY IN APPEARANCE AND ARE ALL SOLIDS AT ROOM
TEMPERATURE EXCEPT MERCURY.
-2. NON-METALS ARE THE SECOND LARGEST ELEMENT GROUPING.
THEY ARE SOLIDS, GASES, AND ONE IS A LIQUID. THE SOLIDS ARE
BRITTLE AND ARE NOT MALEABLE OR DUCTILE. THEY DO NOT
CONDUCT ELECTRICITY OR HEAT WELL EITHER.
-3. METALLOIDS ARE ELEMENTS THAT HAVE PROPERTIES OF BOTH
METALS AND NON-METALS. THERE ARE ONLY 8 ELEMENTS IN THIS
GROUP
-SEE TABLE 6.3 FOR PROPERTIES OF THESE 3 GROUPINGS OF
ELEMENTS.
-DO CYU 6.2 ON PAGE 204 #1-2
6.3 THE SCIENCE AND TECHNOLOGY OF METALLIC ELEMENTS
-METALLURGY IS THE SCIENCE AND TECHNOLOGY OF RETRIEVING
METALLIC ELEMENTS AND MAKING THEM AS USEFUL AS POSSIBLE.
METALLURGY HAS 3 MAJOR PROCESSES.
-EXTRACTION IS WHEN WE SEPARATE THE DESIRED ELEMENT FROM
MINERALS (COMPOUNDS). A MINERAL IS A SOLID PURE SUBSTANCE
THAT OCCURS IN THE EARTH’S CRUST. THE NAMES OF MINERALS
OFTEN END IN “ITE”. HEMATITE IS THE MINERAL NAME FOR IRON.
-MINERALS OCCUR IN ROCK OR ORE. THE METALLIC ELEMENT IS
NOW EXTRACTED IN A 2 STEP PROCESS SHOWN IN 6.12. THIS PROCESS
INVOLVES CONCENTRATION BY PHYSICAL MEANS, AND
DECOMPOSITION BY CHEMICAL MEANS. THE RESULT IS A NEARLY
PURE METAL.
-ONCE THE ORE IS PURE WE CAN MODIFY THE METAL USING
PHYSICAL MEANS. THESE ARE METHODS LIKE BEATING, HEATING,
AND SUDDEN COOLING, AND IT’S CALLED TEMPERING.
-THE PROCESS OF SMELTING IS WHEN WE USE HEAT TO EXTRACT
METAL FROM ORE. THIS PROCESS IS WIDELY USED IN CANADA AND IS
A HUGE INDUSTRY. FOR EXAMPLE, OUR ANNUAL URANIUM SALES ARE
$600M.
-AN ALLOY IS THE MIXTURE OF 2 OR MORE METALS. IT IS STRONGER
AND HARDER THEN PURE METAL. IT IS ALSO EASIER TO MELT AND
RESISTS ELECTRICITY.
-WE CAN MAKE METALS STRONGER WITHOUT MAKING ALLOYS BY A
PROCESS CALLED MODIFICATION. THIS IS WHEN WE ALTER THE
SHAPE, THEN ADD HEAT AND THEN LET COOL IN ITS NEW SHAPE.
-INVESTIGATION 6-E ON PAGE 213. DEMO IN CLASS WITH STUDENTS.
-DO CYU 6.3 ON PAGE 214 #1-4
6.4 FAMILIES OF ELEMENTS
-ALL THE ELEMENTS ON THE EARTH ARE CLASSIFIED INTO 3 MAJOR
GROUPINGS. THEY ARE EITHER METALS (CONDUCT ELECTRICITY),
NON-METALS (DO NOT CONDUCT ELECTRICITY), OR METALLOIDS
(CONDUCT VERY LITTLE BUT HAVE CHARACTERISTICS OF BOTH
OTHER GROUPS).
-ELEMENTS FOUND ON EARTH ARE GROUPED TO MAKE
CLASSIFICATION EASIER. WITHIN THESE 3 MAJOR GROUPINGS ARE
SUBCLASSES CALLED CHEMICAL FAMILIES. A CHEMICAL FAMILY IS
THE TERM USED TO DESCRIBE A GROUP OF ELEMENTS THAT HAS
SIMILAR CHEMICAL PROPERTIES.
-JOHN DALTON’S ATOMIC THEORY, WHICH STATED THAT EACH
ELEMENT HAD A DIFFERENT ATOMIC MASS, HELPED SCIENTISTS PUT
THE ELEMENTS IN ORDER.
-DMITRI MENDELEEV BUILT A PERIODIC TABLE OF ELEMENTS THAT
PUT THE ELEMENTS IN ORDER FROM SMALLEST TO LARGEST IN
ATOMIC MASS. THIS TABLE ALSO PUTS ELEMENTS INTO GROUPS
(FAMILIES) OF SIMILAR CHEMICAL PROPERTIES. VERTICLE GROUPS
ARE CALLED FAMILIES. THERE ARE 9 FAMILIES.
-HORIZONTAL GROUPS ARE CALLED PERIODS AND ARE ARRANGED IN
INCREASING ATOMIC NUMBER.
-INVESTIGATION 6-F ON PAGE 219. DO PARTS 1-3 AND ANSWER ALL THE
“WHAT TO DO” QUESTIONS. DO NOT DO THE “ANALYZE” QUESTIONS.
-DO CYU 6.4 ON PAGE 222 #1-4
-DO CHAPTER AT A GLANCE (ALL) ON PAGE 223
-DO CHAPTER 6 REVIEW ON PAGE 224 #1-15
CHAPTER 7 – MODELS OF ATOMIC STRUCTURE
7.1 PROBING THE ATOM
-THE ATOM IS ELECTRICALLY NEUTRAL BUT HAS POSITIVE CHARGES
CALLED PROTONS AND NEGATIVE CHARGES CALLED ELECTRONS.
J.J.THOMPSON DISCOVERED THE ELECTRON.
-WE USE THIS KNOWLEDGE TO CREATE TELEVISIONS BY USING THE
WORK OF HEINRICH GEISSLER AND HIS GAS DISCHARGE TUBE. (PAGE
229-230)
-ELECTRONS (CATHOD RAYS) WERE SHOT FROM THE CATHOD (-)
TOWARDS THE ANODE (+) BECAUSE OPPOSITES ATTRACT. THIS
CREATES A BEAM AND OUR T.V.’S.
-LET’S CHASE THE ELECTRON>>>>>FLIP TO PAGE 232-233 IN THE TEXT
-THOMPSON CONCLUDED 5 THINGS ABOUT THE ATOM:
1. ALL ATOMS HAVE PROTONS AND ELECTRONS
2. ALL PROTONS ARE THE SAME, ALL ELECTRONS ARE THE SAME
3. PROTONS ARE POSITIVE, ELECTRONS ARE NEGATIVE
4. PROTONS HAVE EQUAL AND OPPOSITE CHARGES
5. PROTONS HAVE MORE MASS THEN ELECTRONS.
-THE RESULT OF ALL THIS RESEARCH ON THE ATOM LED US TO THE
ELECTRON MICROSCOPE WHICH CAN MAGNIFY ITEMS UP TO 800,000
TIMES AS OPPOSED TO THE COMPOUND MICROSCOPE WHICH CAN
MAGNIFY ITEMS UP TO 2000 TIMES.
-PROTONS AND ELECTRON ARE CALLED SUBATOMIC PARTICLES
BECAUSE THEY ARE SMALLER THEN ATOMS.
-INVESTIGATION 7-A ON PAGE 232-233. DO ALL 4 “WHAT TO DO” PARTS
AND ALL OF THE “ANALYZE” QUESTIONS.
-DO CYU 7.1 ON PAGE 235 #1-4
7.2 THE BOHR – RUTHERFORD MODEL
-FOLLOWING THE DISCOVERY OF RADIOACTIVITY BY MARIE CURIE,
ERNEST RUTHERFORD STARTED TO LOOK FURTHER INTO IT. HE
FOUND 3 TYPES OF RADIATION AND NAMED THEM ALPHA (+), BETA (-),
AND GAMMA (NO CHARGE) PARTICLES.
-RUTHERFORD MADE AN EXPERIMENT TO PROBE THE ATOM USING
THE ALPHA PARTICLES AS ATOMIC BULLETS. (PAGE 239) MOST
PARTICLES WENT RIGHT THROUGH, HOWEVER, SOME WERE
DEFLECTED. THIS LED HIM TO BELIEVE THAT 1.THE ATOM WAS
MOSTLY EMPTY SPACE, AND 2. IT HAD A SMALL POSITIVELY CHARGED
NUCLEUS WHERE THE PROTONS WERE LOCATED. THE EMPTY SPACE
IS CALLED THE ELECTRON CLOUD, AND IS THE SPACE THE ELECTRONS
OCCUPY.
-ANOTHER PARTICLE WAS DISCOVERED IN THE NUCLEUS OF AN ATOM.
IT IS CALLED THE NEUTRON AND HAS NO CHARGE BUT HAS A MASS
ROUGHLY EQUAL TO THE PROTON. THE ELECTRON HAS A MASS OF
1/2000 OF THE OTHERS.
-THE OUTCOME OF ALL THIS WORK WAS A MODEL OF AN ATOM THAT
IS USED TODAY. THE NUCELUS (PROTONS, NEUTRONS) WAS IN THE
MIDDLE AND WAS SURROUNDED BY AN ELECTRON CLOUD
CONTAINING ELECTRONS. ELECTRONS GO AROUND THE NUCLEUS IN
SPECIFIC “ORBIT” CALLED ELECTRON SHELLS, DEPENDING ON HOW
MUCH ENERGY THEY HAVE. THIS MODEL IS SOMETIMES CALLED THE
PLANETARY MODEL BECAUSE IT IS SIMILAR TO THE WAY THE EARTH
AND THE PLANETS ORBIT THE SUN.
-ACTIVITY “SUMMARIZING ATOMIC STRUCTURE” ON PAGE 244.
COMPLETE THE TABLE BELOW.
ELECTRON
CHARGE
MASS
LOCATION
-DO CYU 7.2 ON PAGE 244 #1-3
PROTON
NEUTRON
7.3 A NEW BASIS FOR THE PERIODIC TABLE
-MENDELEEV ARRANGED THE PERIODIC TABLE USING CHEMICAL
PROPERTIES AND ATOMIC MASS AS HIS GUIDES. WHEN HE HAD TO
CHOOSE BETWEEN THE TWO, CHEMICAL PROPERTIES WERE USED.
THERE ARE SOME “REVERSALS” YOU WILL SEE ON THE PERIODIC
TABLE.
-HENRY MOSELEY TESTED MENDELEEV’S PERIODIC TABLE BY USING
X-RAYS. HE CONCLUDED THAT THE NUMBER OF PROTONS IN THE
NUCLEUS WAS RESPONSIBLE FOR PERIODICITY (PUTTING ELEMENTS
IN ORDER). THE NUMBER OF PROTONS BECAME KNOWN AS THE
ATOMIC NUMBER. THE ATOMIC MASS NUMBER OF AN ELEMENT IS
THE NUMBER OF PROTONS + NEUTRONS IN THE NUCLEUS.
-SO WHEN IDENTIFYING AN ELEMENT LET’S LOOK AT THIS EXAMPLE:
19
9
F
19 = MASS NUMBER
F = CHEMICAL SYMBOL
9 = ATOMIC NUMBER
-ATOMIC MASS UNITS ARE A 1/12TH RATIO OF THE MASS OF A 126C ATOM.
SO EACH ELEMENT IS COMPARED TO IT AS A RATIO.
-ACTIVITY “ODD COUPLES” ON PAGE 246. USE THE PERIODIC TABLE
AND DO QUESTIONS #1-3.
-DO CYU 7.3 ON PAGE 252 #1-4
-DO CHAPTER AT A GLANCE (ALL) ON PAGE 253
-DO CHAPTER 7 REVIEW ON PAGE 254 #1-12
CHAPTER 8 – CHEMICAL BONDING
8.1 EXPLAINING CHEMICAL FAMILIES
-CLASSIFYING ELEMENTS IN THEIR FAMILIES CAN BE MADE EASIER BY
USING SHELL DIAGRAMS. ELEMENTS IN THE SAME FAMILY ALWAYS
HAVE THE SAME NUMBER OF ELECTRONS IN THE OUTER (VALENCE)
SHELL.
-NOBLE GASES ARE THE FAMILY 18 ON THE PERIODIC TABLE AND
HAVE 8 ELECTRONS IN THE VALENCE SHELL, EXCEPT FOR HELIUM
WHICH HAS 2. WHEN THERE IS 8 ELECTRONS IN THE VALENCE SHELL
IT IS CALLED A STABLE OCTET. THESE GASES ARE UNREACTIVE
(INERT) WITH ANY OTHER ELEMENTS.
-HALOGENS ARE THE FAMILY 17 ON THE PERIODIC TABLE AND HAVE 7
ELECTRONS IN THE VALENCE SHELL. THESE ELEMENTS ARE HIGHLY
REACTIVE AND SEEK TO AQUIRE 1 ELECTRON TO MAKE AN OCTET.
-ALKALI METALS ARE FAMILY 1 ON THE PERIODIC TABLE AND HAVE 1
ELECTRON IN THE VALENCE SHELL. THESE ELEMENTS ARE HIGHLY
REACTIVE AND SEEK TO LOSE THE REMAINING ELECTRON IN ITS
VALENCE SHELL SO IT CAN BECOME AN OCTET.
-ALKALI EARTH METALS ARE FAMILY 2 ON THE PERIODIC TABLE AND
HAVE 2 ELECTRONS IN THE VALENCE SHELL. THESE ELEMENTS ARE
FAIRLY REACTIVE AND SEEK TO LOSE THE REMAINING 2 ELECTRONS
IN ITS VALENCE SHELL SO IT CAN BECOME AN OCTET.
-CREATE A TABLE SIMILAR TO THE ONE ON PAGE 260 IN YOUR TEXT.
FILL IN THE ELECTRON SHELL DIAGRAMS.
-DO CYU 8.1 ON PAGE 264 #1-3
8.2 IONIC COMPOUNDS
-IONIC BONDS OCCUR BETWEEN ELEMENTS FROM THE ALKALI
FAMILY AND ELEMENTS OF THE HALOGEN FAMILY. EACH ELEMENT
IS VERY CLOSE TO BECOMING AN OCTET IN ITS VALENCE SHELL.
ALKALI METALS NEED TO LOSE AN ELECTRON WHILE HALOGENS
NEED TO GAIN ONE.
-WHEN THESE TWO TYPES OF ELEMENTS COME TOGETHER, THE
HALOGEN TAKES THE ELECTRON FROM THE ALKALI METAL. NOW
EACH ELEMENT HAS AN OCTET. THE ALKALI METAL NOW HAS A
SLIGHT POSITIVE CHARGE WHILE THE HALOGEN HAS A SLIGHT
NEGATIVE CHARGE. SINCE THEY NOW ARE OF OPPOSITE CHARGES,
THEY ATTRACT TO FORM AN IONIC COMPOUND.
-ELEMENTS ARE NATURALLY NEUTRAL SO AN ION IS AN ELEMENT
THAT HAS EITHER GAINED OR LOST ELECTRONS. WHEN AN ALKALI
METAL LOSES AN ELECTRON IT BECOME POSITIVE AND IS CALLED A
CATION. WHEN A HALOGEN GAINS AN ELECTRON IT BECOMES
NEGATIVE AND IS CALLED AN ANION.
-TYPICALLY ELEMENTS IN THE FIRST 15 FAMILIES ARE CATIONS AND
ELEMENTS IN FAMILIES 16-18 ARE ANIONS, BUT THIS IS NOT ALWAYS
THE CASE.
-THESE IONS FORM IN EACH OF THE FOLLOWING GROUPS/FAMILIES:
1.
+1
2.
+2
3-12. +2, +3, +4
13.
+3
14.
+4
15.
+5 MOSTLY, BUT CAN BE -3
16.
-2 MOSTLY, BUT CAN BE +6
17.
-1
18.
NO IONS FORMED
-CRYSTAL LATTICE IS A REGULAR REPEATING PATTERN WITHIN AN
IONIC COMPOUND SUCH AS SALT (NaCl). IONIC COMPOUNDS ARE HARD
AND DO NOT CONDUCT ELECTRICITY WELL BECAUSE THE IONS DO
NOT MOVE. WHEN IN SOLUTION THEY CAN MOVE ABOUT, THEREFOR
CONDUCTING ELECTRICITY.
-DO CYU ON PAGE 267 #1-5
-START TO GROW CRYSTALS
8.3 MOLECULAR COMPOUNDS
-WHEN YOU HAVE MORE THEN 1 ATOM YOU HAVE A MOLECULE.
MOLECULAR COMPOUNDS ARE FORMED BY MORE THEN 1 ATOM
SHARING ELECTRONS IN AN ARRANGEMENT CALLED A COVALENT
BOND. IN THIS TYPE OF BOND, THE ATOMS DO NOT BECOME
CHARGED. OXYGEN IS AN EXAMPLE OF A COVALENT BOND > O2.
-THE DIFFERENCE BETWEEN IONIC AND COVALENT BONDS IS THE
ATTRACTION BETWEEN MOLECULES. IONIC MOLECULES HAVE A
STRONG ATTRACTION BETWEEN MOLECULES AND FORM HARD
CRYSTALS. COVALENT BONDS HAVE A WEAK ATTRACTION BETWEEN
MOLECULES AND DO NOT FORM LARGE, HARD STRUCTURES.
-MOLECULAR COMPOUNDS HAVE RELATIVELY LOW MELTING AND
BOILING POINTS (WEAK ATTRACTIVE FORCES), SOFT IN TEXTURE
(SAME), AND POOR CONDUCTORS (NO IONS OR FREE ELECTRONS).
-CARBON IS A UNIQUE ELEMENT IN THAT IT CAN BE USED IN THE
FORM OF GRAPHITE TO MAKE PENCILS AND TO CONDUCT
ELECTRICITY. IT IS LINKED BY STRONG COVALENT BONDS THAT
FORM SHEETS OF GRAPHITE.
DIAMONDS ARE ANOTHER FORM OF CARBON THAT HAS BEEN UNDER
EXTREME PRESSURE AND TIME. BOTH GRAPHITE AND DIAMONDS ARE
MADE OF STRONG COVALENT BONDS. HOWEVER, THE CARBON ATOMS
ARE JOINED TOGETHER IN DIFFERENT WAYS.
-GRAPHITE FORM SHEETS OF ATOMS. DIAMONDS FORMS 4 COVALENT
BONDS WHICH CREATE A 3 DIMENSIONAL NETWORK. THIS
ARRANGEMENT OF ATOMS MAKES DIAMOND THE HARDEST KNOWN
NATURAL SUBSTANCE ON EARTH.
-MONOMERS ARE SUB-MOLECULES. A POLYMER IS A STRING OF
MONOMERS. WE USE POLYMERS (ETHYLENE) TO FORM PLASTIC
PRODUCTS LIKE MILK, BLEACH, AND JUICE CONTAINERS.
-INVESTIGATION 8-B ON PAGE 274. COMPLETE THE TABLE ON
LOOSELEAF USING THE ITEMS PROVIDED. COMPLETE THE 3 STEPS IN
“WHAT TO DO”.
-ACTIVITY “SLIMY CONNECTIONS” ON PAGE 275. FOLLOW
INSTRUCTIONS WHILE RECORDING OBSERVATIONS AT EACH STEP IN
“WHAT TO DO”. DO BOTH OF THE “WHAT DID YOU DISCOVER”
QUESTIONS ON THE SAME LOOSELEAF AS YOUR OBSERVATIONS.
-DO CYU 8.3 ON PAGE 276 #1-5
8.4 CHEMICALS IN YOUR LIFE
-CHEMICALS HAVE HELPED IN PRODUCING FOOD SINCE THE NUMBER
OF FARMERS HAS DRAMATICALLY SHRUNK IN THE LAST 100 YEARS.
NITROGEN FERTILIZER IS OFTEN USED TO HELP PLANT GROWTH. IT
COMES IN THE FORM OF AMMONIA (NH3) WHICH IS A GAS, BUT IS
COMPRESSED INTO A LIQUID WHEN USED. SOIL FERTILIZER IS
AMMONIUM NITRATE (NH4NO3).
-2 KINDS OF PESTICIDES ARE USED WIDELY. HERBICIDES ARE USED TO
CONTROL WEEDS. INSECTICIDES ARE USED TO CONTROL INSECTS.
-THE CHEMICAL ETHYLENE (C2H4) IS USED TO RIPEN FRUIT. IT IS ALSO
USED IN CREATING POLYMERS FOR PLASTICS.
-MEDICINE ALSO USES CHEMICALS. DRUGS LIKE ASPRIN AND
ANESTHETICS HAVE HELPED TO EASE PAIN IN PATIENTS.
-DO CYU 8.4 ON PAGE 280 #1-3
-DO CHAPTER AT A GLANCE (ALL) ON PAGE 281
-DO CHAPTER 8 REVIEW ON PAGE 282 #1-17, 19, 22-27
-DO UNIT 2 REVIEW ON PAGE 288 #1-46