Chemistry
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Element Challenge 1
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Element Challenge 2
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Element Challenge 3
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Atomic Math 1
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Atomic Math 2
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Atomic Math 3
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Atomic Math 4
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Common Compound 1
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Common Compounds 2
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Compound Challenge 1
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Compound Challenge 2
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Compound Challenge 3
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Compound Challenge 4
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Compound Challenge 5
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Periodic Table 1
Mav Mark
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Test Day
Take out a sheet of paper and a pencil.
Clear your desk.
Physical Properties

Properties of matter that can be observed or
measured without changing the identity of the
matter

Ex.




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Color, Smell, Mass, Volume, Density
Conductivity (ability to transfer energy)
State {physical form (solid, liquid, gas)}
Malleability (ability to be hammered into thin sheets)
Ductility (ability to be drawn into a wire)
Solubility (ability to dissolve in another substance)
Chemical Properties

Chemical Properties: describe a substance
based on its ability to change into a new
substance with different properties


Ex. Flammability, reactivity
Metal reacts with oxygen to form rust.
Physical Properties

Properties of matter that can be observed or
measured without changing the identity of the
matter

Ex.


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
Color, Smell, Mass, Volume, Density
Conductivity (ability to transfer energy)
State {physical form (solid, liquid, gas)}
Malleability (ability to be hammered into thin sheets)
Ductility (ability to be drawn into a wire)
Solubility (ability to dissolve in another substance)
Physical changes

A change that affects one
or more physical properties
of a substance, but doesn’t
change its chemical
identity.

Ex: breaking a pencil,
melting, dissolving sugar in
water, cutting your hair,
crushing an aluminum can
Physical changes


An easy way to tell if something is
a physical change, is to determine
if it can be undone.
Ex:

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
Ice cubes that melt in a bowl can be
refrozen.
A broken pencil still writes.
Hair doesn’t turn into something else
when it’s cut.
Chemical Change


A change that occurs when
one or more substances are
changed into entirely new
substances with different
physical properties.
Ex. Baking a cake,
effervescent tablets fizzing in
water, a car rusting


States of Matter
There are four states of matter:
solid, liquid, gas, and plasma
Matter is in constant motion.
Pure Substance

Pure substances are made of only one type of
particle.

Elements: A pure substance that cannot be
separated into simpler substances by physical or
chemical means.

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Ex. Carbon (C), Oxygen (O), Gold (Au)
Represented by 1 or 2 letters, first letter always capital
Each element has unique physical and chemical
properties that can be used to identify them.
For the most part…elements can be divided into three
categories.
Pure substances: Elements
Elements
Metals
Nonmetals
Metalloids
Pure substances: Elements

Metals: Shiny, good conductors of electricity,
malleable, ductile


Nonmetals: Dull, poor conductors of electricity,
brittle and unmalleable


Ex. Iron, Copper
Ex. Sulfur, Neon
Metalloids: Semiconductors of electricity,
somewhat malleable and ductile, some shiny
some dull

Ex. Boron, Silicon
Periodic Table
Pure Substance: Compounds
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Compounds: A pure substance that is composed
of two or more elements that are chemical
combined.
Have a fixed ratio of elements.
When compounds form they take on new
characteristics.
Ex. Na + Cl → NaCl or 2H2 + O2 → 2H2O
Common Compounds
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NaCl: Sodium Chloride (Table Salt)
H2O: Dihydrogen Monoxide (Water)
CO2: Carbon Dioxide
CH4: Methane
C6H12O6: Glucose (Sugar)
Pure Substance: Compounds
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Since compounds are composed of elements
that are chemical combined, they must
undergo chemical changes to be broken
down into the constituent elements.
Most of the substances that we deal with
everyday are compounds, because most
elements are too reactive to remain as a
single element.
Ex: Proteins, CO2, NH4
Mixtures

A mixture is a combination of two or more
substances that are NOT chemically
combined.
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Ex. Pizza, Salt water
Mixtures can be separated by physical means.
(filtration, centrifuge, evaporation, mechanical
separation, magnetism)
Do not have fixed ratios.
Mixtures :Solutions

Homogenous (solution): Particles are
uniform throughout
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Solute: substance that is dissolved
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Examples: Salt water, alloy (metals dissolved in
metals) Brass=zinc+copper
Ex: Salt
Solvent: substances that is doing the dissolving

Ex. Water (Universal Solvent!)
Mixtures :Solutions

Solubility: basically how much of the solute
can be completely dissolved by the solvent

Increases with:

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Temperature (except with gases)
Surface Area
Stirring
Atoms
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An atom is the smallest particle into which an
element can be divided and still be the same
substance. (Building block of matter)
Composed of…


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Protons
Neutrons
Electrons
Atoms
Particle
Charge
Mass
Location
Proton
(+)
1 amu
Nucleus
Neutron
Neutral
1 amu
Nucleus
Electron
(-)
Almost zero
Electron
Cloud
Atoms

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Atomic number: tells the number of protons
Mass number: # protons + # neutrons
Atomic mass: average of the masses of the
existing isotopes in an element
Isotopes: Elements that have the same # of
protons, but a different # of neutrons


Some isotopes are radioactive (carbon dating)
Naming: Isotopes are named for the element and
then the atomic mass (Carbon-14)
Practice

Determine the number of protons, neutrons,
and electrons in the following:

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Potassium (K)
Oxygen (O)
Sodium (Na)
Helium-3 (3He)
Ions

Atoms that have either gained or lost one or
more electrons. Therefore they have either a
positive or negative charge.

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Cation: (+) Positive charge
Anion: (-) Negative charge
Atoms: Electrons
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Electrons orbit the nucleus of the atom.
For the Bohr model electrons are placed in orbitals
by the formula 2n2, where n=energy level
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So for the first energy level:
The second energy level:
The third energy level:
2(1)2=2
2(2)2=8
2(3)2=18
Reactivity
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All elements want to achieve noble gas
configuration.
They will donate or accept electrons to achieve this
configuration.
The most reactive elements are very close to
achieving noble gas configuration and they readily
achieve it!
Ideally they want 8 electrons in their outer shell!
Valance Electrons: outer electrons
The Periodic Table
Why is the Periodic Table
important to me?

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The periodic table is
the most useful tool to
a chemist.
You get to use it on
every test.
It organizes lots of
information about all
the known elements.
Pre-Periodic Table Chemistry
…
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…was a mess!!!
No organization of
elements.
Imagine going to a
grocery store with no
organization!!
Difficult to find
information.
Chemistry didn’t make
sense.
Dmitri Mendeleev: Father of
the Table

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HOW HIS WORKED…
Put elements in rows
by increasing atomic
weight.
Put elements in
columns by the way
they reacted.
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SOME PROBLEMS…
He left blank spaces for
what he said were
undiscovered elements.
(Turned out he was
right!)
He broke the pattern of
increasing atomic
weight to keep similar
reacting elements
together.
The Current Periodic Table
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Mendeleev wasn’t too far off.
Now the elements are put in rows by
increasing ATOMIC
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NUMBER!!
The horizontal rows are called periods and
are labeled from 1 to 7. Periods tell the
number of energy levels the atom has.
The vertical columns are called groups are
labeled from 1 to 18.
Groups…Here’s Where the
Periodic Table Gets Useful!!
 Elements
in
the same
group have
similar
chemical and
physical
properties!!

(Mendeleev did that on
purpose.)
Why??
• They have the same
number of valence
electrons.
• They will form the same
kinds of ions.
Families on the Periodic Table
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Columns are also grouped
into families or groups.
Families may be one
column, or several columns
put together.
Families have names rather
than numbers. (Just like
your family has a common
last name.)
Hydrogen


Hydrogen belongs to a
family of its own.
Hydrogen is a diatomic,
reactive gas.
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(Br, I, N, Cl, H, O, F)
Hydrogen was involved in
the explosion of the
Hindenberg.
Hydrogen is promising as
an alternative fuel source
for automobiles
Alkali Metals
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1st column on the
periodic table (Group 1)
not including hydrogen.
Very reactive metals,
always combined with
something else in
nature (like in salt).
Soft enough to cut with
a butter knife
1 electron in outer
orbital
Alkaline Earth Metals
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Second column on the
periodic table. (Group 2)
Reactive metals that are
usually combined with
nonmetals in nature.
Not as reactive as alkali
metals.
Several of these
elements are important
mineral nutrients (such as
Mg and Ca)
2 electrons in outer shell
Transition Metals
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Elements in groups 312
Less reactive harder
metals
Includes metals used in
jewelry and
construction.
Metals used “as metal.”
Higher densities and
melting points than
groups 1 and 2.
Lanthanides and Actinides

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Transition metals placed here to keep periodic
table from being too wide.
Named for the elements that they follow.
Lanthanides:
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Actinides:
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Shiny, reactive metals, used in steel manufacturing
Radioactive (unstable)
Synthetic past U!
Boron Family/Group
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Elements in group 13
Aluminum metal was
once rare and
expensive, not a
“disposable metal.”
Contains 1 metalloid
and 4 metals
3 electrons in outer
level
Solid at room
temperature
Carbon Family/Group

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
Elements in group 14
Contains elements
important to life and
computers.
Carbon is the basis for
an entire branch of
chemistry.
Silicon and Germanium
are important
semiconductors.
4 electrons in outer shell
Nitrogen Family

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Elements in group 15
Nitrogen makes up
over ¾ of the
atmosphere.
Nitrogen and
phosphorus are both
important in living
things.
The red stuff on the
tip of matches is
phosphorus.
5 electrons in outer
shell
Oxygen Family/Group
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Elements in group 16
Oxygen is necessary
for respiration.
Many things that stink,
contain sulfur (rotten
eggs, garlic,
skunks,etc.)
6 outer electrons
Halogens
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Elements in group 17
Very reactive, volatile,
diatomic, nonmetals
Always found combined
with other element in
nature .
Used as disinfectants
and to strengthen teeth.
7 outer electrons
The Noble Gases

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Elements in group 18
VERY unreactive,
monatomic gases
Used in lighted “neon”
signs
Used in blimps to fix
the Hindenberg
problem.
Have a full valence
shell.
Reactivity


Noble Gases are at the far right of the
periodic table.
Reactivity increases as you go to the left and
the top of the periodic table.
Chemical Bonding




A chemical bond is the force of attraction that
holds two atoms together.
The key to bonding is found in the number of
valance electrons.
Valance electrons: electrons that are in the
outermost energy level of an atom
Remember the goal is to have 8 valance
electrons (exception H and He)
Chemical Bonding

The oxidation number of an atom is the
charge that atom would have if the compound
was composed of ions.
Bonding: Ionic, Covalent,
Metallic

Ionic bond: forms between a metal and a
nonmetal where the metal gives up an
electron to the nonmetal and the resulting
oppositely charged ions attract each other.
Bonding: Ionic, Covalent,
Metallic


Covalent bond: involves the sharing of
electrons between atoms
Can exist as a single, double, or triple bond
(C, O, N)
Bonding: Ionic, Covalent,
Metallic


Metallic bond: gives metals their unique
characteristics due to delocalized
electrons that can flow throughout the
metal
Occurs in transition metals.
Predicting bonding




First determine how
many e- are in the
atoms outer shell.
Next determine whether
it is likely to lose or gain
e- or if it is able to share
e-.
Ionic=nonmetal+metal
Covalent =
nonmetal + nonmetal
Predict whether the following will
form ionic, covalent, or metallic
bonds.

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Carbon and Carbon
Cadmium and Cadmium
Phosphorous and Fluorine
Strontium and Selenium
Chemical Reactions


A chemical reaction is the process by which
one or more substances undergo change to
produce one or more different substances.
Clues a reaction has occurred:




Gas formation (bubbles)
Precipitate forms (solid)
Color change
Energy change (heat absorbed or given off)
Chemical formula



A chemical formula is a shorthand way of
writing a compound.
It represents the element by the chemical
symbol.
It represents the quantity of the element by
the subscript.
Writing Covalent Chemical
Formulas

Prefixes to know:


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
MonoDiTriTetraPenta-
1
2
3
4
5

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HexaHeptaOctaNonaDeca-
6
7
8
9
10
Use prefixes to tell you the number of atoms of that element!
Writing Covalent Chemical
Formulas

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Carbon dioxide
Dinitrogen monoxide
Dihydrogen monoxide
Triphosphorous pentoxide
CO2
N 2O
Writing Ionic Chemical
Formulas

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Occurs between metals and nonmetals.
The compound must be neutral.

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
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Sodium chloride
Beryllium oxide
Magnesium chloride
Calcium chloride
Chemical Equations

Reactants → Products

C + O2 → CO2

***All equations must be balanced!!!***
The law of conservation of mass: mass can
neither be created nor destroyed!
The law of conservation of energy: energy can
neither be created nor destroyed!


Practice balancing equations

Count the atoms!

H2 + O2 → H2O



Place coefficients to
balance the atoms.



Check and finish
balancing.
H=2
O=1
H2 + O2 → 2H2O


H=2
O=2
H=2
O=2
H=4
O=2
2H2 + O2 → 2H2O


H=4
O=2
H=4
O=2
Types of Reactions

Synthesis



A + X → AX
Na + Cl2 → NaCl
Decomposition


AX → A + X
H2CO3 → H2O + CO2
Types of Reactions

Single-replacement reaction



A + BX → AX + B
Zn + HCl → ZnCl2 + H2
Double-replacement reaction


AX + BY → AY + BX
NaCl + AgF → NaF + AgCl
Types of Reactions

Rusting (Slow oxidation)


4Fe + 3O2 → 2Fe2O3
Combustion (Fast oxidation)

CH4 + 2O2 → CO2 + 2H20 + Heat
Energy and reactions

Exothermic: energy is released (energy may be in
form of light, electrical, or thermal)


2Na + Cl2 → 2NaCl + energy
Endothermic: energy is absorbed or goes into the
reaction (ex. Photosythesis)

2H2O + energy → 2H2 + O2
How a reaction gets started

Activation energy: minimum amount of
energy needed for substances to react.
Factors that affect reaction
rates



Temperature: an increase in temperature
increases the rate of the reaction
Concentration: an increase in the amount of
reactants increases the rate of the reaction
Surface area: Grinding reactants into powder
can increase the rate of reaction
Factors that affect reaction rates

Catalysts: a substance that speeds up a reaction
without permanently being changed.

Enzymes: proteins in human’s that act as catalyst.
Factors that affect reaction
rates

Inhibitors: a substance that slows down or
stops a chemical reaction

Preservatives act as inhibitors to prevent spoilage
Star Formation




Sun made mostly of Hydrogen. The H exist
in an extremely high energy state called
plasma.
In stars the pressure is so high that the nuclei
of atoms, which normally repel, are joined
together. (Nuclear Fusion)
Two Hydrogen atoms collide and produce
helium.
Two Helium atoms collide and produce one
helium and two Hydrogen atoms.