Download Final Exam Review

Final Exam Review
pick up final exam review and periodic
table from the back.
7:55 - 9:55 AM
10:05 AM - 12:05 PM
Dismissal
Tuesday, Dec. 17
1st Period Final
2nd Period Final
at 12:05 PM
Wednesday, Dec. 18
3rd Period Final
4th Period Final
at 12:05 PM
Thursday, Dec. 19
5th Period Final
6th Period Final
at 12:05 PM
Friday, Dec. 20
7th Period Final
0 or 8th Period Final
after your last exam
Announcements
• If you have not taking any exam…you MUST
do it by Thursday afternoon
• I will be here Thursday until 4:30pm
• If you would like to do a makeup on a final
grade, it is due at the latest Monday during
lunch.
– For the paper exam you can do test corrections.
– After Monday, I will not allow any more makeup
exams.
Tips for studying for final exams…
• DO NOT PROCRASTINATE
• Start from what you just learned and work
your way back.
• Take study breaks!
• Get enough sleep.
• Teach someone else. If you can teach it, you
understand it!!!
• RELAX! It is JUST a final….NO NEED TO STRESS!
Make sure you add Trigonal Pyramidal
to note cards to study.
It’s 3-1 (107)
Rules for Naming Covalent Compounds
1. The “Most Metallic” Atom goes first
2. The amount of atoms goes first in the name
followed by the name of the atom then the last
atom has nonmetal root -ide
1. eg: N2S DiNitrogen monosulfide
3. If “O” is repeating, take out an O
1. eg: CO = Carbon Monoxide, NOT Carbon monooxide
4. Do not put Mono if the first atom only has one
1. Eg. CO is NOT monocarbon monoxide
Pre-Fixes to memorize
#
Prefix
1
mono
2
di
3
tri
4
tetra
5
penta
6
hexa
7
hepta
8
octa
9
nona
We will start with # 47…
Ionic Vs. Covalent
Ionic
Between a metal and a nonmetal
(left of staircase) (right of staircase)
Covalent
Between two nonmetals
(right of staircase)
Electrons are transferred from the metal to Electrons are shared between two
nonmetal.
nonmetals
1) metal + nonmetal root – ide
2) Transition metals and group 4
Copper (II) = Cu2+
3) Polyatomic Ions
#nonmetal (most electronegative) +
#nonmetalroot –ide
Needing Exams from!
Lab Practical
Elias
Frederick
Exam
Mariella
Mariel
Announcements
• Thursday Afternoon is tentative
– Due to illness
Diatomic Gases – Gasses found
naturally as diatomic molecules
• Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Iodine (I2)
Bromine (Br2)
• Have No Fear Of Ice Cold ROOTBeer
Models of the Atom
Dalton’s
Greek
modelmodel
(400 B.C.) (1803)
1803 John Dalton
pictures atoms as
tiny, indestructible
particles, with no
internal structure.
1800
1805 ..................... 1895
Thomson’s plum-pudding
model (1897)
1897 J.J. Thomson, a British
scientist, discovers the electron,
leading to his "plum-pudding"
model. He pictures electrons
embedded in a sphere of
positive electric charge.
1900
1905
1910
1915
1920
Rutherford’s model
(1909)
1911 New Zealander
Ernest Rutherford states
that an atom has a dense,
positively charged nucleus.
Electrons move randomly in
the space around the nucleus.
1925
1930
1935
1940
Bohr’s model
(1913)
1913 In Niels Bohr's
model, the electrons move
in spherical orbits at fixed
distances from the nucleus.
Charge-cloud model
(present)
1926 Erwin Schrödinger
develops mathematical
equations to describe the
motion of electrons in
atoms. His work leads to
the electron cloud model.
1945
1932 James
Chadwick, a British
physicist, confirms the
existence of neutrons,
which have no charge.
Atomic nuclei contain
neutrons and positively
charged protons.
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 125
Match The Models
Dalton
Thomson’s Plum
Pudding
Rutherford
Nucleus
Bohr
Energy
Levels
Chadwick,
Neutrons
Sub-Particles in the Atom
Location
in the Atom
Sub-Particle
Mass
Charge
proton
~1 a.m.u.
1+
in nucleus
neutron
~1 a.m.u.
0
in nucleus
electron
~0 a.m.u.
1-
orbits nucleus
atomic.mass.unit= a.m.u. ~ 1.992 ×10−27 kg or 1/12 the mass of C-12
How can I remember how many
protons or electrons there are?
Just remember the A.P.E. rules!
•atomic number
=
•number of protons =
•number of electrons
Now, how do I remember how many
protons there are?
Just remember the M.A.N.!
•mass number
-
•Atomic number
=
•number of neutrons
Mass Number
• mass number= protons + neutrons
• always a whole number
• NOT on the
Periodic Table!
+
+
+
Neutron
Electrons
eNucleus
+ +
e-
ee-
ee-
+
Nucleus
Carbon-12
Neutrons 6
Protons
6
Electrons 6
Proton
Writing Isotopes
• Put the mass number after the name of the
element
• carbon- 12
• carbon -14
• uranium-235
– Or
Mass #
12
Atomic #
6
California WEB
C
Isotopes
• Dalton was wrong.
• Atoms of the same element can have different
numbers of neutrons.
• different mass numbers.
• called isotopes.
Average Atomic Mass
• massed average of all isotopes on the
Periodic Table
• round to 2 decimal places
Avg.
(mass)(%) + (mass)(%)
Atomic =
100
Mass
Avg.
(mass)(decimal) + (mass)(decimal)
Atomic =
Mass
Roy G. Biv
Electrons Absorbing Energy
Photon coming into atom collides with
electron. Photons are energy.
+
The electron is “excited” to a higher energy level with is newly
increased energy from absorbing the photon.
And later…
The electron cannot remain in that excited state indefinitely
+
Energy is released and light is observed
Hydrogen Spectrum
The black bars are the colors that a hydrogen atom absorbs. The
other colors pass through the atom un-absorbed.
What does this have to do with electron
arrangement in atoms?
• When all electrons are in the lowest possible
energy levels, an atom is said to be in its
GROUND STATE.
• When an atom absorbs energy so that its
electrons are “boosted” to higher energy
levels, the atom is said to be in an EXCITED
STATE.
The Math
Only 3 equations
• No Energy:
c = λv
• With Energy
E = hv
E= hc
λ
• c is always
3.00 x 108 m/s
• h is always
6.626 x 10-34 J s
Blocks in the Periodic Table
Taking Measurements
Scientific Notation
• For example, instead of writing 0.0000000056,
we write 5.6 x 10-9.
• Always one number to the left of decimal…NO
MORE NO LESS!
• Exponent determines whether number is
really big (positive) or really small (negative)
Significant Figures
• Series of Questions:
• Is the decimal absent or present?
• Present
– Start from the pacific ocean side (left).
– Start counting from the first number that’s NOT 0
– Keep counting don’t stop
• Atlantic
– Start from the Atlantic ocean side (right).
– Start counting from the first number that’s NOT 0
– Keep counting don’t stop
Density
• D = m/V
• Density = mass (g) / volume (mL)
Metric Conversions
Physical and Chemical Changes
• Physical
– A physical change does not produce a new substance.
Changes in state or phase (melting, freezing, vaporization,
condensation, sublimation) are physical changes. Examples
of physical changes include crushing a can, melting an ice
cube, and breaking a bottle.
• Chemical
– A chemical change makes a substance that wasn't there
before. There may be clues that a chemical reaction took
place, such as light, heat, color change, gas production,
odor, or sound. The starting and ending materials of a
physical change are the same, even though they may look
different.
Signs of Chemical Changes
• Bubbles of gas appear
• A precipitate forms. When mixing a pair of soluble reactants in solution,
the sudden appearance of a solid that 'rains down' (precipitates) into the
bottom of the container is a sign that a reaction has occurred. Sometimes
the precipitate particles are too small to settle out; in this case, look for a
cloudy solution.
• A color change occurs
• The temperature changes
• Light is emitted. Sometimes energy is released by bond-forming reactions
in the form of light. This occurs in most combustion reactions. Living things
that glow in the dark- such as fireflies, funguses, and deep sea creaturesproduce light without heat, using chemical reactions
Law of Conservation of Mass
• In a reaction, the starting material must equal
the ending material
• Example:
• What is the mass of
the NaCl after the
experiment ?
Elements, Compounds, Mixtures
• Element:
consists of only one kind of atom, cannot be broken down into a simpler
type of matter by either physical or chemical means, and can exist as
either atoms (e.g. argon) or molecules (e.g., nitrogen).
A molecule consists of two or more atoms of the same element, or different elements, that are chemically
bound together. Note that the two nitrogen atoms which comprise a nitrogen molecule move as a unit.
• Compound:
consists of atoms of two or more different elements bound together,
can be broken down into a simpler type of matter (elements) by chemical means (but not by
physical means),
has properties that are different from its component elements, and
always contains the same ratio of its component atoms.
•
Mixture:
consists of two or more different elements and/or compounds physically intermingled,
can be separated into its components by physical means, and
often retains many of the properties of its components.
http://www.chem.purdue.edu/gchelp/atoms/elements.html
Accuracy and Precision
• Accuracy refers to the agreement between
experimental data and a known value. You can think
of it in terms of a bullseye in which the target is hit
close to the center, yet the marks in the target aren't
necessarily close to each other.
• Precision
Precision refers to how well experimental values
agree with each other. If you hit a bullseye precisely,
then you are able to hit the same spot on the target
each time, even though that spot may be distant
from the center.
Intensive vs. Extensive
• Intensive
– Depends on the substance
– Same for all substances
– Eg: aluminum has a density of 2.7g/mL no matter
the size, shape, or mass
• Extensive
– depends on the outside amount
– Not the same
– Eg: mass, volume…exc
Periodic Table
• Periodicity: regular variations (or patterns) of
properties with increasing atomic number. Both
chemical and physical properties vary in a
periodic (repeating) pattern.
• Group: vertical column of elements (“family”)
• Period: horizontal row of elements
Periodic
Table
and
Periodicity
Chemistry: The Periodic Table and Periodicity
1. Who first published the classification of the elements that is the basis of our periodic
table today?
DMITRI MENDELEEV
2. By what property did Mendeleev arrange the elements?
ATOMIC MASS
3. By what property did Moseley suggest that the periodic table be arranged?
ATOMIC NUMBER
4. What is the periodic law?
THE PROPERTIES OF THE ELEMENTS REPEAT PERIODICALLY
5. What is a period? How many are there in the periodic table?
A HORIZONTAL ROW IN THE PERIODIC TABLE; 7
6. What is a group (also called a family)? How many are there in the periodic table?
A VERTICAL COLUMN IN THE PERIODIC TABLE; 18
The Periodic Law
• Mendeleev understood the ‘Periodic Law’
which states:
• When arranged by increasing atomic number,
the chemical elements display a regular and
repeating pattern of chemical and physical
properties.
Metals, Nonmetals, & Metalloids
1
Nonmetals
2
3
4
5
Metals
6
7
Metalloids
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 349
Transition metals
lanthanides
actinides
halogens
noble gases
alkali metals
alkaline earth metals
Elements with similar chemical behavior are in the same group.
Metals
• Metals are lustrous
(shiny), malleable,
ductile, and are good
conductors of heat
and electricity.
• They are mostly solids
at room temp.
• What is one
exception?
Mercury
(Hg)
Nonmetals
• Nonmetals are the
opposite.
• They are dull, brittle,
nonconductors
(insulators).
• Some are solid, but
many are gases, and
Bromine is a liquid.
Metalloids
• Metalloids, aka semi-metals
are just that.
• They have characteristics of
both metals and nonmetals.
• They are shiny but brittle.
• And they are
semiconductors.
• What is our most important
semiconductor?
Silicon
(Si)
Periodic trends
Identifying the patterns
Metallic Characteristics
metallic character increases
metallic character increases
Periodic Trends
• atomic radius.
• Radius is the distance from the center of the
nucleus to the “edge” of the electron cloud.
Atomic Radii
Atomic Radii
• Trend: decreases across a period
WHY???
– As the # of protons in the nucleus increases, the positive
charge increases and as a result, the “pull” on the electrons
increases.
• Trend: increases down a group
WHY???
– The atomic radius gets bigger because electrons are added
to energy levels farther away from the nucleus.
Atomic Size Trends
+
-
Particles with opposite
charges attract
one another.
+ +
Particles with like charges
repel one another.
-
Depends on:
2+
1+
2-
1-
• 1. Amount of charge
2+
2+
2-
2-
• 2. Distance between charges
Distance – down a group
Number of Protons – across a period
So which one do we use???
• Distance trumps number of protons.
• Otherwise we would see an increase in the attractive force
as you move from smaller to larger atoms down a column.
Ionization Energy
• Definition: energy required to remove outer electrons
Ionization Energy
Ionization Energy
• Trend: increases across a period
• WHY???
• All the atoms in the same period
– Increasing nuclear charge
• Trend: decreases down a group
• WHY???
– Electrons are further away from the positive “pull”
of the nucleus and therefore easier to remove.
Electronegativity
• Definition: the tendency of an atom to
attract electrons to itself when chemically
combined with another element
Electronegativity
• Trend: increases across a period
(noble gases excluded!)
• WHY???
– Nuclear charge is increasing, atomic radius is
decreasing; attractive force that the nucleus can
exert on another electron increases.
• Trend: decreases down a group
• WHY???
– The electrons are farther away from the nucleus;
decreased attraction, so decreased
electronegativity
ElectronegativityTrends
Summing Up Periodic Trends
Summing Up Periodic Trends
Which has the largest atomic radius?
7. Br- Br
8. Al+ Al
As an atom gains electrons, the atom gets bigger
As an atom loses electrons, the atom gets smaller