Chemistry ReviewChemistry Review

Classification of Matter

Chemical vs. Physical ChangeChemical vs. Physical Change

Chemical changeChemical change (or reaction):(or reaction): new new substances with different properties are formed.substances with different properties are formed.

Physical change:Physical change: no new substances are no new substances are formed. A change in state or shape is a physical formed. A change in state or shape is a physical change.change.

Chemistry – What is it?Chemistry – What is it?

How do you know if a chemical How do you know if a chemical reaction has occurred?reaction has occurred?

1)1) Formation of a gasFormation of a gas

2)2) Formation of a precipitate (solid)Formation of a precipitate (solid)

3)3) Color changeColor change

4)4) Energy is released (exothermic)Energy is released (exothermic)

5)5) Energy is needed (endothermic)Energy is needed (endothermic)

Please note that with any chemical Please note that with any chemical change, there is change, there is alsoalso a change in a change in energyenergy..

Lab Safety Recognize hazards!!!!Recognize hazards!!!! No book bags or large jackets in the labNo book bags or large jackets in the lab Always wear safety goggles and lab Always wear safety goggles and lab

aprons, especially when working with aprons, especially when working with hazardous materials and liquidshazardous materials and liquids

Do not eat or drink in the lab.Do not eat or drink in the lab. Long hair should be tied up.Long hair should be tied up. Do not have combustible materials near a Do not have combustible materials near a

flameflame Clean up your lab bench once you are Clean up your lab bench once you are

done.done. Look for WHMIS labels on chemical bottles Look for WHMIS labels on chemical bottles

(see page 35 in text)(see page 35 in text)

Compressedgas

Oxidizing material

Materials causingother toxic effects

Corrosivematerial

Flammable and combustible material

Materials causingimmediate and serious toxic effects

Biohazardous infectious material

Dangerously reactivematerial

Use safe procedures & techniquesUse safe procedures & techniques Tie back long hairTie back long hair Always wear safety glassesAlways wear safety glasses Do not eat or drink in the lab.Do not eat or drink in the lab. Never taste chemicalsNever taste chemicals Do not directly inhale chemicalsDo not directly inhale chemicals Please stand while doing labsPlease stand while doing labs

Respond to emergencies sensiblyRespond to emergencies sensibly Inform a teacher if someone requires assistanceInform a teacher if someone requires assistance If chemicals are spilled on skin, rinse with water for 20 If chemicals are spilled on skin, rinse with water for 20

minutesminutes If you break something or spill something, please If you break something or spill something, please

inform a teacher immediately. Do NOT handle broken inform a teacher immediately. Do NOT handle broken glass!glass!

If a fire starts, inform a staff member immediately – If a fire starts, inform a staff member immediately – STOP… DROP… ROLL!!!STOP… DROP… ROLL!!!

IF YOU ARE NOT SURE ABOUT SOMETHING…

ASK A TEACHER!!!!

V. Classifying MatterV. Classifying Matter

MatterMatter is anything that has mass is anything that has mass and occupies and occupies spacespace

Matter can be classified into two Matter can be classified into two main categories: main categories: HeterogenousHeterogenous & & HomogenousHomogenous

Matter

Heterogeneous(Non uniform mixture)

i.e. cookie dough

Homogeneous(uniform matter)

i.e. water

Homogeneous Mixture / Solutioni.e. NaCl (aq)

Pure Substancesi.e. Lead

Compoundsi.e. NaCl(s)

Elementsi.e. O2(g)

* This chart found on page 36*

- An atom is the smallest particle of an element which still has the characteristics of the element. (O2(g), Cl2(g), K(s))

- Compounds contain more than one type of atom combined in a definite proportion. (NaCl(s), KBr(s), HCl(aq))

1) Gravel and Sand

2) Vinegar

3) Nitrogen

4) Salt

ElementsElementsI. Classifying ElementsI. Classifying Elements

MetalsMetals NonmetalsNonmetals MetalloidsMetalloids-Solids @ SATPSolids @ SATP-ShinyShiny-DuctileDuctile-GoodGood conductorsconductors-Lose electronsLose electrons

to form positive to form positive ionsions

-solids, liquids, solids, liquids, gasesgases-Gain electrons Gain electrons to form negative to form negative ionsions-BrittleBrittle-Poor conductorsPoor conductors-Lack lusterLack luster

-Have Have characteristics characteristics of metals & of metals & nonmetalsnonmetals-Located near Located near staircasestaircase

II. The Periodic TableII. The Periodic Table

John Alexander NewlandsJohn Alexander Newlands Arranged elements in order of increasing Arranged elements in order of increasing

atomic massesatomic masses Noticed some properties recurring over Noticed some properties recurring over

and over again – he called this the periodic and over again – he called this the periodic lawlaw

Dmitri MendeleevDmitri Mendeleev Published the periodic table Published the periodic table

of elementsof elements Very confident as he left spaces Very confident as he left spaces

empty – assumed those elements empty – assumed those elements were not yet discoveredwere not yet discovered

- Mendeleev used the terms - Mendeleev used the terms FAMILYFAMILY and and PERIODPERIOD to describe the table’s organization. to describe the table’s organization.

FAMILY/GROUP:FAMILY/GROUP: elements in vertical elements in vertical columns – have similar properties.columns – have similar properties.

Reactivity INCREASES from Reactivity INCREASES from top to bottom within groups top to bottom within groups 1 and 21 and 2

Reactivity DECREASES from top Reactivity DECREASES from top to bottom in groups 17 & 18. to bottom in groups 17 & 18. (Fluorine is the most reactive (Fluorine is the most reactive non-metal)non-metal)

PERIOD:PERIOD: elements in elements in horizontal rows horizontal rows – these elements change – these elements change from metals to nonmetals.from metals to nonmetals.

Groups of ElementsGroups of Elements Alkali Metals:Alkali Metals:

Group 1 metalsGroup 1 metals Soft, silver coloured metals Soft, silver coloured metals

that react violently with Hthat react violently with H22O O to form basic solutionsto form basic solutions

Most reactive: cesium & Most reactive: cesium & franciumfrancium

Alkaline Earths: Group 2A metalsLight, reactive metals that form oxide coatings when exposed to air

Transition Metals:Transition Metals: Elements in groups 3 to 12Elements in groups 3 to 12 Exhibit a wide range of Exhibit a wide range of

propertiesproperties

Metalloids:Metals very close to the “staircase” lineThey have properties of metals and non-metals.

Halogens:Halogens: Group 17, non-metals, Group 17, non-metals,

highly reactive.highly reactive. Fluorine is the most Fluorine is the most

reactivereactive

Noble Gases:Noble Gases: Group 18Group 18 Generally unreactiveGenerally unreactive (inert)(inert)

Lanthanides:Lanthanides: atomic numbers 58-71 atomic numbers 58-71 Actinides:Actinides: atomic numbers 90-103 atomic numbers 90-103

III. Atomic TheoriesIII. Atomic Theories Dalton:Dalton:

all matter is composed of tiny indivisible all matter is composed of tiny indivisible particles called atomsparticles called atoms

atoms of the same element have identical atoms of the same element have identical propertiesproperties

atoms can be combined to form new atoms can be combined to form new substancessubstances

Thompson:Thompson: Discovered the Discovered the electronelectron – a – a

subatomic particle with a negative subatomic particle with a negative charge.charge.

He proposed the atom was a He proposed the atom was a positive sphere with negative positive sphere with negative electrons embedded in the sphere.electrons embedded in the sphere.

Rutherford:Rutherford: Suggested the existence of the Suggested the existence of the protonproton – –

subatomic particles with positive chargesubatomic particles with positive charge His “gold” experiment led to the His “gold” experiment led to the

discovery of the protondiscovery of the proton Proposed that all atoms have a positive Proposed that all atoms have a positive

central region called the central region called the nucleusnucleus

Bohr:Bohr: Electrons orbit the Electrons orbit the

positive nucleus in positive nucleus in certain orbitals – certain orbitals – electrons cannot exist electrons cannot exist between orbitalsbetween orbitals

The higher the energy The higher the energy level of an electron, level of an electron, the further it is from the further it is from the nucleusthe nucleus

Energy Level

Maximu

m Number

of electron

s (e-)1 2

2 8

3 8

Quantum Mechanics:Quantum Mechanics: Highly mathematicalHighly mathematical There is a region around the nucleus in There is a region around the nucleus in

which there is a high probability of which there is a high probability of finding an electron – the motion of the finding an electron – the motion of the electron is unknown.electron is unknown.

Currently accepted modelCurrently accepted model

VI. Back to the Periodic VI. Back to the Periodic Table…Table…

What do these tell us?- atomic number - atomic

mass- group number - period number

In each atom, the number of protons equals In each atom, the number of protons equals the number of electrons.the number of electrons. The number of neutrons can be found by The number of neutrons can be found by subtractingsubtracting the the atomic numberatomic number from the from the atomic atomic massmass

V. Simple IonsV. Simple Ions Ions are charged atoms.Ions are charged atoms. Metals lose electrons to become positively charged. Metals lose electrons to become positively charged. Groups 1, 2, & 3 will lose electrons to become similar to the Groups 1, 2, & 3 will lose electrons to become similar to the

nearest noble gas.nearest noble gas. Non-metals will Non-metals will

gain electrons gain electrons to obtain a to obtain a net negative net negative chargecharge

All atoms want to have a stable (full) All atoms want to have a stable (full) outer energy ringouter energy ring They want to be more like noble gasesThey want to be more like noble gases

To become stable the atoms will gain To become stable the atoms will gain or lose electrons (whichever is or lose electrons (whichever is easiest) to fill the outer energy level.easiest) to fill the outer energy level. When they When they loselose electrons, they become electrons, they become

positivelypositively charged charged When they When they gaingain electrons, they become electrons, they become

negativelynegatively charged charged

Ion FormationIon Formation

When atoms lose or gain electrons, they When atoms lose or gain electrons, they become become IONS.IONS.

To name an ion, follow these rules:To name an ion, follow these rules:

1) If ion is non-metal, change the ending to “-ide”1) If ion is non-metal, change the ending to “-ide”- ex. Chlorine - ex. Chlorine → Chloride→ Chloride

Bromine → BromideBromine → Bromide

2) If ion is a metal, call it the same and add the 2) If ion is a metal, call it the same and add the word “ion” after it. word “ion” after it.

- ex. Sodium → Sodium ion- ex. Sodium → Sodium ion Iron → Iron ionIron → Iron ion

How do you calculate the charge of an How do you calculate the charge of an ion?ion?

1)1) Find the noble gas that the element Find the noble gas that the element is closest to on the periodic table is closest to on the periodic table (does not have to be in the same (does not have to be in the same period)period)

2)2) Calculate if it would be easier to Calculate if it would be easier to gain or lose electrons to get the gain or lose electrons to get the same number of electrons as the same number of electrons as the closest noble gas.closest noble gas.

3)3) Calculate how many electrons the Calculate how many electrons the element would gain or lose. (When element would gain or lose. (When you gain electron the ion becomes you gain electron the ion becomes positive, when you lose, the ion positive, when you lose, the ion becomes negative)becomes negative)

4)4) Record the charge as a superscript Record the charge as a superscript following the element’s symbol.following the element’s symbol.

O

Gain electrons

2 electrons

O2-

VI. IsotopesVI. Isotopes

ISOTOPES are ISOTOPES are elements that have elements that have the same atomic the same atomic number but number but different atomic different atomic masses.masses.

The differences in The differences in atomic masses are atomic masses are due to the addition due to the addition or removal of or removal of neutrons.neutrons.

Protons?

Neutrons?

Electrons?

Protons?

Neutrons?

Electrons?

Protons - 10

Neutrons - 10

Electrons - 10

Protons - 35

Neutrons - 45

Electrons - 36