Download Ions

Atoms with a charge
• Ion: any atom that has a net electric charge; not
neutral
• If the atom is not neutral, then there must be a
different number of protons and electrons
• First determine the number protons and electrons
(either use the periodic table or it will be given to
you)
• Figure out the difference between number of protons
and electrons.
• If there are more electrons than protons, the charge is the
negative difference
• If there are more protons than electrons, the charge is the
positive difference
• Once you figure this out, write the symbol of the
element with the charge to the top right.
• For example: Lithium with 2 electrons is written as Li+1
Sodium
Sodium
(Loses e-)
11 Protons +11
11 Electrons -11
Net charge 0
11 Protons
+11
10 Electrons -10
Net charge
+1
Positive ions lose electrons. Atoms can lose more
than one electron (cations)
Chlorine ClGains e-
17 Protons
18 Electrons -18
Net charge
-1
Negative ions gains electrons (anions)
+17
• An atom of oxygen has
10 electrons. What is its
charge?
• An atom of Calcium has
18 electrons. What is its
charge?