1. Do Now Dec 22
- Explain the difference between a
proton, an electron and a neutron.

2. The Periodic Table Elements
• Boxes in the periodic table contain a lot of
information. To understand this information, it is
necessary to refer to the periodic table’s key
Atomic Number
Element Symbol (a capital
letter or a capital followed
by a lower case letter)
Atomic Mass
8
O
Oxygen
15.999
Element Name

3. Atomic Number
• Atomic number- the number of protons in the nucleus of an
atom
• Equal to the number of electrons to make an atom neutral
+
++
-
-
-
What would
be the atomic
number of this
atom?

4. Atomic Mass
• Atomic mass- the total number of protons and
neutrons in an atom’s nucleus
• Expressed in Atomic Mass Units (amu)
• Each proton or neutron has a mass of 1 amu
+
++
-
-
-
What would be the atomic
mass of this atom?
+  3
 4
3 protons + 4 neutrons =
an atomic mass of 7 amu
Why did we not account for the
electrons when calculating the
atomic mass?

5. Atomic Mass
• Atomic mass- the total number of protons and
neutrons in an atom’s nucleus
• Expressed in Atomic Mass Units (amu)
• Each proton or neutron has a mass of 1 amu
+
++
-
-
-
What would be the atomic
mass of this atom?
+  3
 4
3 protons + 4 neutrons =
an atomic mass of 7 amu
Why did we not account for the
electrons when calculating the
atomic mass?

6. Sub-atomic Particles
Size Comparison
(protons, neutrons, electrons, & quarks)
Size in
atoms
Size in
meters
(m)
Atom 1 10-10
Nucleus __1__
10,000
10-14
Proton or
Neutron
___1___
100,000
10-15
Electron
or Quark
_____1____
100,000,000
10-18
(at largest)
+
+
+
+
+
++
-
-
-
-
--
-
-
+

7. Stations
• 1. Students will be able to calculate the atomic
mass unit in order to determine atomic mass
unit. Complete math section in textbook on
page 93.
• 2. Students will be able to infer information
about electromagnetic energy in order to
answer questions based on information. PSSA
LTS orange pages 76 to 79.