Atomic Structure and the Periodic Table
This chapter we have discussed different subatomic particles. These particles are protons, electrons and
neutrons. Below you will review and complete exercises over the different types of subatomic particles.
Protons:
If you want to determine the amount of protons in an atom you can look at the atomic number on the
periodic table.
Element
Symbol
# of protons
Iron
Fe
26
Gold
Au
79
Sodium
Na
11
Oxygen
O
8
Uranium
U
92
Neutrons:
If you want to determine the number of neutrons in an atom you can look at atomic mass-number on
the periodic table.
Equation you can use to find the number of neutrons:
Element
Mass
# of protons
Iron
56 amu
26
Gold
197 amu
79
Sodium
23 amu
11
Oxygen
16 amu
8
Uranium
238 amu
92
# of Neutrons
30
118
12
8
146
When an atom has a different number of neutrons but the same number of protons it is an isotope.
The average atomic mass can be calculated using the following equation:
Electrons:
Finishing this definition: A valence electron is…..
a single electron or one of two or more electrons in the outer shell of an atom that is responsible for the
chemical properties of the atom.
An ion is a charged particle formed from the gain or loss of electrons. A cation is a positively charged ion
formed from the gaining of one or more electrons. An anion is a negatively charged ion formed from the
loss of one or more electrons.
Element
Atomic
#
# of
protons
# of
electrons
Group
#
Cation
or Anion
Ionic
charge
Carbon
6
6
6
14
anion
4+
Potassium
19
19
19
1
cation
1+
Oxygen
8
8
8
16
N/A
2-
Arsenic
33
33
33
15
anion
3-, 3+, 5+
Neon
10
10
10
18
N/A
0
Boron
5
5
5
13
cation
3+, 3-
Nitrogen
7
7
7
15
N/A
3-
Calcium
20
20
20
2
cation
2+
This table shows the charges for a selected number of element’s ions. Use this chart to answer the
following questions.
In general, do nonmetals form anions or cations?
anions
In general, do metals form anions or cations?
cations
Which nonmetal appears to be an exception to these guidelines?
Copper
Review:
Review this worksheet and put a ‘star’ next to five pieces of information that seem most important for
you to remember for the exam. Afterwards, put a question mark next to three pieces of information
that you should review and study in more detail.