Download UNIT 1 Review

UNIT 1 & 2 Review
First Quarter Exam Material
Periodic Table
 The
Periodic Table of
Elements shows all of the
known elements, arranged
by Increasing atomic
number
The Atom
The smallest particle of an
Element is an Atom
 To the right
are the atoms
in the Element
Gold

http://www.chem.utoronto.ca/staff/DHIRANI/stm-np.jpg
Atomic Models
 Democritus


Basic shapes to identify “atoms”
No subatomic particles
Atomic Models
 Dalton


Invisible and Indivisible
No subatomic particles
Atomic Models
 Thomson


Plum Pudding
Positive substance containing negative
particles
Atomic Models
 Rutherford


Protons in Nucleus
Electrons around Nucleus
Atomic Models
 Bohr


Protons and Neutrons in Nucleus
Electrons around Nucleus in Orbits
N
Atomic Models
 Electron


Cloud
Protons and Neutrons in Nucleus
Electrons around Nucleus in a cloud
formed my probability
N
Subatomic Particles
Particle
Charge
Mass
Location
Proton
+1
1 amu
nucleus
Neutron
0
1 amu
nucleus
Electron
-1
0
Outside the
nucleus
Isotope
 An
Isotope is an atom with
the same number of protons,
but a different number of
neutrons. Changing the
neutrons changes the mass
of the atom.
Isotope Examples
 Carbon-13
and Carbon-12
 The 13 and the 12 represent
different masses for each
atom. The “-” is a dash, not a
negative sign.
 13C
and12C are also ways to
indicate different masses
Protons

Atomic number = # Protons

Carbon has 6 Protons
Electrons

Atomic number = # Electrons

Unless there is a charge
Fluorine has 9 electrons
 F-1 has 10 electrons
 Sodium has 11 electrons
 Na+1 has 10 electrons

Neutrons

Atomic mass - # protons =
# neutrons
Carbon-12
 (mass)12 – (protons)6 = 6 neutrons

Carbon-13
 (mass)13 – (protons)6 = 7 neutrons

Drawing Bohr Models


Protons and Neutrons in
nucleus
Electrons in rings outside
of nucleus
Ring
Ring
Ring
Ring
Ring
Ring
Ring
1
2
3
4
5
6
7
=
=
=
=
=
=
=
2 electrons
8 electrons
8 electrons
18 electrons
18 electrons
32 electrons
32 electrons
Chemical Formulas
 Represents
the number of
each type of element bonded
together in a compound
 Remember to Multiply when
there are parenthases
Calcium Phosphate,
Ca3(PO4)2
Ca-3, P-2, O-8
13 total atoms in one molecule of the compound.
Kinetic Theory

Kinetic Theory states that
atoms and molecules are in
constant Motion
Phase Changes


Point C = Boiling
from Liquid to Gas
Point B = Liquid
Form
Point A = Melting
from Solid to Liquid
Temperature

Time
The plateau (flat part of the graph) represents the phase change. The
temperature of the substance does not rise (or fall) until all of it has
changed phases
A
B
C
Moles
Amedeo Avagadro came up
with the “Chemist’s Dozen”
 1 mole contains 6.02 x 1023
Particles

Mole Continued
 The
mass of one mole of any
element is the same as the
molar mass.


Example: 1 mole of C = 12.011 grams
This means that 6.02 x 1023 atoms of
Carbon has a mass of 12.011 grams.
Sig Figs




Placeholders are NOT significant
figures.
With Addition/Subtraction line up the
decimals.
With Multiplication/Division the
number of sig figs is based on the
number that has the least number of
sig figs.
Refer to the sig fig worksheet for
complete rules.
Answers to sig fig
problems
Determine the number of significant figures in each
measurement.



508.0 L ________4____________
0.008204 g_________4___________
Round all numbers to four significant figures. Write the
answers to e-h in scientific notation.



847950 kg ___847900_________
38.5421 g____38.54__________
Complete the following addition and subtraction
problems. Round off the answers when necessary



43.62 + 51.0 + 8.73 = ______103.3_________
258.3 - 257.11 =_____1.2__________
Complete the following calculations. Round off the
answers to the correct number of significant figures.



24 x 3.25 = _____78__________
120 / 10 = ________10__________
Density
 Density
is a ratio of mass
and volume. How tightly
packed?
D
=

 Density
= Mass
Volume
Separating Mixtures
 In
the separating mixtures
lab the four methods of
separation were listed.




Filtration
Decanting
Evaporation
Distillation
Mixtures

A Heterogeneous mixture
is one where the different
parts can be easily seen.
o A Homogeneous mixture
is one where the particles are
mixed so well that the
separate parts cannot be seen.
Saturated vs Unsaturated

Saturated: Contains the
maximum amount of dissolved
solute for a given amount of
solvent at a specific
temperature and pressure.
• Unsaturated: Contains less
dissolved solute for a given
temperature and pressure
than a saturated solution; has
further capacity to hold more
solute.
Changes
A Chemical change occurs
when atoms interact and
rearrange to form new
substance.
 A Physical change occurs when
properties of the substance
changes, but the identity of the
substance does not change.

Making and Breaking
Bonds
 When
a bond is broken
energy is required.
 When
a bond is made energy
is released.