Basic Chemistry
for
Earth Science
The Periodic Table
• Family/Group: vertical columns
• Period: the horizontal rows on the periodic
table
• Elements are pure substances that cannot be
broken down into a more simple substance.
They are found on the periodic table.
• An atom is the smallest part of an element you
can have and still have the properties of that
element.
• All atoms are make-up of subatomic particles.
The 3 subatomic particles are:
– Protons
– Neutrons
– Electrons
• The nucleus is the center of an atom.
• Protons have a positive charge and are found in the nucleus.
• Electrons have a negative charge and are found in a “cloud”
outside of the nucleus.
• Neutrons are neutral and are found in the nucleus.
• The number of protons determine the identity of an element.
• The Atomic Number tells you the number of protons and
electrons (unless it is an ion).
• The Mass Number tells you protons + neutrons.
• Neutrons = Mass Number - # of Protons
Element Mass # Atomic # Protons Electrons Neutrons
Gold
197.0
79
79
79
118
Magnesium
24.31
26.98
40.08
22.99
12
13
20
11
12
13
20
11
12
13
20
11
12
13
20
11
Aluminum
Calcium
Sodium
• An Isotopes are atoms of an element that
have the same number of protons, but a
different number of neutrons.
Element Mass # Atomic # Protons Electrons
Neutrons
Carbon
12
6
6
6
6
Carbon
14
6
6
6
8
• A ion is an atom that has gained or lost
electrons. If an atom loses electrons it is
metal. If an atom gains electrons it is
non-metal.
Element
Mass #
Atomic # Protons
Electrons Neutrons Charge
Calcium
40.08
20
20
18
20
+2
Chlorine
35.45
17
17
18
18
-1
Nitrogen
14.01
7
7
10
7
-3
Metals
Nonmetals
- Lose electrons easily
- Gain electrons easily
- form positive ions
- from negative ions
- dominates the periodic table
- do not form ionic bonds with
other metal ions
• A compound is two or more elements
chemically combined.
– Examples:
•
•
•
•
Water H2O
Table Salt NaCl
Baking Soda Na2CO3
Vinegar HC3H3O2
• A molecule is the smallest part of a compound
that you can have and still have the properties
of the compound.
• A mixture is a material system made up by two
or more different substances which are mixed
but are not combined chemically.
• A covalent bond is a bond formed when
electrons are shared.
• An ionic bond is a bond formed when electrons
are either gained or lost from one element to
another.
A metallic bond is a bond formed when
electrons are shared in large amounts.
• -like a sea of electrons that are shared by all
atoms
• Ionic Bonds are like TYRANTS. They take what
they want.
• Covalent Bonds are like socialists. They share
what they need.
• Metallic Bonds are like Anarchists. They run
around sharing what they need, but with no
thought of ownership.