Transcript PS7aChemistryReviewRevised

Chemistry
It’s a REVIEW
See how YOU DO
ELEMENT, COMPOUND, or NEITHER???
OXYGEN
SULFUR
KOOL AID
NEON
NITROGEN
AMMONIA
DIAMOND
IRON
BREAD
HYDROCHLORIC ACID
SUGAR WATER
JELLO
ALCOHOL
PROTEIN
SEAWATER
ICE
COAL
CARBON
HYDROGEN
URANIUM
AIR
CARBON DIOXIDE
SODIUM
WATER
SODIUM CHLORIDE
GOLD
STEEL
COFFEE
VINEGAR
CARDBOARD
State 2 or 3 ways to identify a substance as
one of these three choices
What are Physcial Properties of a
Substance? Chemical Properties?
Physical Properties Include…
DENSITY…COLOR…LUSTER…FRACTURE…
CRYSTAL STRUCTURE… MALLEABILITY…
DUCTILITY… FREEZING (MELTING) POINT…
BOILING (CONDENSATION) POINT…
CONDUCTIVITY…MAGNETIC PROPERTIES
…FLAMMABILITY…and any other
characteristic that could be used to identify
that substance
Chemical Properties Include…
The characteristic ways in which
compounds/elements react when they come
into contact with one another
Phase Changes (Physical Changes!)
?
?
?
LIQUID
?
?
?
SOLID
GAS
Phase Changes (Physical Changes!)
LIQUID
MELTING
BOILING
FREEZING
CONDENSATION
SUBLIMATION
DEPOSITION
SOLID
GAS
Phase change diagram
T
E
M
P
E
R
A
T
U
R
E
◦
C
D
E
C
B
A
TIME
Can you model a) the molecular changes, b) potential
and kinetic changes for each indicated time interval?
Element = one type of atom only
Cu = copper
Hg = mercury
Br2 = bromine
I2 = iodine
What other categories are there? What is a mixture?
Elements cannot be separated into anything simpler by
human means – only smaller particles with the same
characteristics!
Compounds and mixtures can be separated into simpler
components.
Mixtures show the characteristics of the substances that
they contain…not a new set of characteristics…they are
relatively easy to separate.
Compounds show new characteristics, not those of the
substances they contain…they are generally harder to
separate.
Compound = 2 or more types of atoms
Copper Sulfate - CuSO4
Sodium Chloride - NaCl
How is an atom different from a molecule??
Atom = smallest basic unit of any element
Molecule = more than one atom, usually
more than one type of atom
isopropyl alcohol = C, H, and O atoms
glucose = C, H, and O atoms
Assemble each of these into one of
three groups
Neutral
heavy (one atomic unit) proton
light (1/1800 atomic unit)
positive
Electron
neutron
orbits the central region
different for the isotope forms
Constant for an element
negative
neutron
inside nucleus
when these change, ions form
heavy (one atomic unit)
which element?
35
Br
# protons??
# neutrons??
Atomic number??
#electrons?
79.904
Atomic mass?
Mass number??
Periodic Table – an organization of elements,
based upon their characteristics
How do they
differ??
Compound……mixture
Polar………….non-polar
Acid………………………………base
Physical change
………chemical change
Polar molecules have charged regions;
non-polar molecules do not
Water = polar
molecule
Carbon Dioxide =
non-polar molecule
Chemical Change
Or
Physical Change??
Bread rises.
Ice melts.
Baking soda + vinegar fizzes.
A raw egg is cooked.
Instant coffee dissolves in water.
Chocolate melts in a warm room
Alcohol boils.
Paint dries.
A photosynthesizing plant produces sugar.
Radioactive
Elements – In
what way do
they change?
Radioactive elements give off radiation,
which changes their elemental identity
This process is called radioactive decay.
Bonding
It’s all about electrons!!
Practice with Periodic Table groups I through VIII
Electron locations in the atom (model)
1. How many electrons does the neutral atom contain?
2. The first 1 or 2 are placed into Energy Level #1
3. Energy Level 2 holds up to 8 electrons.
4. Energy Level 3 holds up to 8 electrons.
5. Energy Level 4 hold up to 8 electrons…etc.
NOW…Keep track of the electrons in the outer energy level!
Where on the Periodic Table are the elements with 1 outer
level electron?
NUMBER OF VALENCE ELECTRONS = GROUP NUMBER!
Rule #1: EVERY ATOM REACTS TO GET 8 VALENCE
ELECTRONS
IONIC BOND
Lithium + Chlorine
Li becomes +1 ion, Cl becomes -1 ion
COVALENT BOND
4 HYDROGEN ATOMS + 1 CARBON ATOM = 1 METHANE MOLECULE
(NO IONS ARE FORMED)