Summary
Chapter 1-2
General, Organic, & Biological Chemistry
Janice Gorzynski Smith
CH 1-2 Concepts to be Familiar With
 Classification of matter: pure substances & mixtures
 Homogeneous vs Heterogeneous
 Distinguish the difference between chemical and physical properties &
changes
 We represent uncertainty with significant figures
 You do not need to memorize Sig Fig rules
 Scientific Notation
 Conversions within the metric system and non metric units
 Temperature conversions
 Density & Specific gravity
 Familiarity with how compounds will be drawn
 Molecular formulas
 Structure of an atom: protons, neutrons, electrons
 Atomic number, isotope mass number, atomic weight
 Navigate the periodic table: properties shared within a group, trends,
metals/metalloids/nonmetals
 Determine valance electrons & draw electron dot representations
 Ionization Energy & Atomic Size
Conversions & Equations To Memorize
Unit Conversions
Equations
For metric units (m, kg, s, K, mole):
mega (M) 106
kilo (k) 103
centi (c) 10-2
milli (m) 10-3
micro (μ) 10-6
nano (n) 10-9
Pico (p) 10-12
Density = mass / Volume
d = m/V
dH2O = 1 g/mL = 1 g/cm3
Time conversions: dhrms
1 mL = 1 cm3
T(kelvin) = T(°C) + 273.15
Specific Gravity =
density substance / density of water
y x 10x
Coefficient:
A number
between
1 and 10.
Exponent:
Any positive
or negative
whole number.
Elements & Molecules
A
Z
X
Elements on
the Periodic
Table
X = Element symbol (ie O = oxygen)
A = Isotope Mass Number = # protons + # neutrons
Z = Atomic Number = # protons
atomic number
6
C
element symbol
12.01
atomic weight (amu) = weighted
average of atomic weight of isotopes
Molecular Formula: AxBy
Drawing Molecules:
Methane
CH4
H
H
C
H
H
Ex: CH3O
Properties of Groups
1A
2A
B
B
7A
8A
Alkali Metals
Alkaline Earth
Metals
Transition
Metals
Lanthanide &
Actinide
Halogens
Nobel Gases
Very reactive
Reactive
Metals
Metals except
for H
+2 ions
Form ions
with several
different
charges
(oxidation
states)
+1 ions
React with
Oxygen to
form
compounds
that dissolve
into alkaline
solutions in
water
Oxygen
compounds
are strongly
alkaline
Many are not
water soluble
Tend to form
Reactive
+2 and +3 ions
Form diatomic
Lanthanides
molecules in
58 – 71
elemental
state
Actinides
90 – 103
-1 ions
Actinides are
radioactive
Salts with
alkali metals
Inert
Heavier
elements have
limited
reactivity
Do not form
ions
Monoatomic
gases
Properties of Metals, Nonmetals, Metalloids
Metals
• Metallic luster,
malleable, ductile,
hardness variable
• Conduct heat and
electricity
• Solids at room
temperature with the
exception of Hg
• Chemical reactivity
varies greatly: Au, Pt
unreactive while Na, K
very reactive
Nonmetals
• Brittle, dull
• Insulators, nonconductors of electricity
and heat
• Chemical reactivity
varies
• Exist mostly as
compounds rather then
pure elements
• Many are gases, some
are solids at room temp,
only Br2 is a liquid.
Metalloids
• Properties intermediate
between metals and
nonmetals
• Metallic shine but
brittle
• Semiconductors:
conduct electricity but
not as well as metals:
examples are silicon and
germanium
Valence Electrons
Example: Determine the valence electrons
of Selenium (Se):
1. Find Se on the periodic table
2. Focus on just the row (period) Se is in
3. Count the number of electrons in the s
and p orbitals (ie, count to Se from the
left side of the row)
Count the number of elements in the row (period) that lead up to the element (Se).
Remember, do NOT count the transition metals, lacthanides, and actinides.
1
2
X
X
X
X
X
X
Electron Dot Symbols:
Represent the valence electrons by
drawing them around the element
symbol for Selenium.
X
X
X
X
Se
3
4
5
6
Periodic Trends
Size
INCREASING
Ionization Energy
INCREASING