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Density is the amount of matter there is in a
certain amount of space.
Density = Mass / Volume
Unit is g / cm3
Frank has a paper clip. It has a mass of 9g
and a volume of 3cm3. What is its density?
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Atoms are composed of Protons, Neutrons,
and Electrons.
Protons and neutrons are found in the
nucleus and electrons are in shells outside
the nucleus.
The Atomic number is the number of protons
and electrons in a neutral atom.
The number of neutrons can be found by
subtracting the number of protons from the
atomic mass.
Each element has a specific number of
protons and that number cannot be changed.
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Isotopes are atoms of the same element that
have a different number of neutrons.
There are two different ways to indicate an
isotope.
◦ Boron-10
Boron-11
◦ Or 1735 Cl the top number is the mass number and
the bottom number is the atomic number.
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The periodic table is an organization of all of
the elements by properties and by atomic
number.
Columns are called “Groups” and the group
also tells us how many valence electrons an
atom of an element contains. Elements in
each group have similar chemical properties.
Rows are called “Periods” and the period tells
us how many electron shells an atom of an
element contains.
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The periodic table is divided into 3 regions:
◦ Metals, Nonmetals & Metalliods
◦ What are some properties of each?
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Make sure to study your notes on page 20 for
each of the families on the Periodic Table.
Structures of the atoms:
◦ Bohr Diagrams:
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First shell = 2 electrons
Second shell = 8 electrons
Third shell = 18 electrons
Fourth shell = 32 electrons
 Practice drawing Al
◦ Electron Dot Diagrams:
 List only the chemical symbol and ONLY the valence
electrons that the element contains.
 Practice drawing Cl
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When atoms bond they can gain, lose, or
share electrons
◦ An ion is an atom that has gamed or lost an
electron making it have a net charge
◦ A Cation is an ion with a positive charge. The atom
has lost electrons.
◦ An Anion is an ion with a negative charge. The
atom has gained electrons.
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Each group on the Periodic Table will
gain/lose electrons and will have a different
charge called the Oxidation Number.
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Octet Rule: Every atom wants 8 outer valence
electrons in order to become stable. They
can achieve this by gaining, losing, or sharing
electrons.
This gaining, losing, and sharing is called
chemical bonding.
◦ Ionic Boding
 Losing of electrons
 Forms between metals and non-metals
 Forms crystalline solids with high melting points
◦ Covalent Bonding
 Sharing of electrons
 Forms between two non-metals.
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Study your notes for naming bonds
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Law of Conservation of Matter – states that in a
chemical reaction matter can be neither created
or destroyed.
The mass you have before the reaction has to
equal the mass after the reaction.
There are several signs of a chemical reaction
◦ Light given off, the formation of a precipitate,
production of a gas, heat given off and color change.
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Practice Balancing Chemical Equations
◦ Remember that you cannot change the subscript only
the coefficient.
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Direct Combination or Synthesis Reaction
◦ A + B = AB
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Chemical Decomposition or Analysis reaction
◦ AB
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Single Displacement
◦ A + BC
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AC + B
Double Displacement
◦ AB + CD
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A+B
AD + CB
Practice Classifying Chemical Equations
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Atoms decay when the strong force is not
large enough to hold a nucleus together.
Energy and particles are given off. The larger
the elements are unstable and tend to decay.
Nuclei with too few or too many neutrons
compared to the protons are radioactive and
will decay.
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There are 3 particles that can be given off
during decay
Alpha
Decay
Beta Decay
Gamma
Radiation
What is
released?
2 protons
and 2
neutrons
(Helium
gas)
Electron
from
nucleus
(proton
changes)
Gamma
Rays
Particles or
EM waves
Particle
Particle
EM Wave
Interesting
facts
Not harmful Can
unless
penetrate
inside the
some skin
body
Destroys
DNA
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The amount of time it takes for half the nuclei
in a sample to decay is called the half-life.
Half-life can vary greatly from a few seconds
to thousands or millions of years.
Problem:
◦ If a human body contained 50g of C-14 and now
had only 25g, how old is the body?
◦ C-14 is 12.5g?
◦ Hint: half-life of Carbon-14 is 5,730 years.
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When atoms combine the form molecules
(two or more of the same element) or
compounds (two or more different elements).
Molecules of elements and molecules of
compounds are both pure substances (must
be separated by chemical means).
Mixtures are not pure substances (can be
separated by physical means). Can be
Homogeneous or Heterogeneous.
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Solid, Liquid, Gas – Remember how the
particles are moving in each
What happens as you add heat to each state
of matter?
Kinetic Theory
◦ All matter is composed of small particles (atoms)
◦ Particles are in constant motion
◦ Particles are colliding with each other and with the
walls of their container.
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According to Boyle’s Law – as pressure
increases, volume decreases.
◦ P1V1 = P2V2
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According to Charles Law – as temperature
increases, volume increases.
◦ V1 \ T1 = V2 \ T2
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Solute – the substance being dissolved.
◦ Example: Salt
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Solvent – the substance doing the dissolving.
◦ Example: Water
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A concentrated solution is a solution that has
a large amount of solute.
A dilute solution is a solution that has a small
amount of solute.
Solubility is the maximum amount of solute
that can be dissolved in a given amount of
solvent at a given temperature.
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Saturated – contains all the solute that a
solvent can hold at a given temperature.
Unsaturated – a solution that can dissolve
more solute at a given temperature.
Supersaturated – a solution that contains
more solute than can be dissolved at a given
temperature.
Solubility Curves
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Stirring – brings more fresh solvent into
contact with more solute.
Crystal size – increases the surface area by
creating smaller particles.
Temperature – causes the solvent to bump
into the solute and dissolve faster.
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