Ions &
Ionic
Bonding
Ion: any atom or group of atoms that has an
electrical charge. Since protons and neutrons
are fixed in the nucleus, an electron must be
lost or gained to create an ion.
Cation: when a neutral atom (same number of
p+and e-) gives up an electron, the positively
charged ion that results is called a cation.
Anion: when a neutral atom gains an electron,
the negatively charged ion that results is
called an anion.
Anions are named using the name of the
element but ending in ide and the word ion.
Cl-1 Chloride ion
P-3 Phosphide ion
Cations are named using the name of the
element and the word ion.
Ca+2 Calcium ion
Li+1 Lithium ion
Be
Na
A beryllium atom has 4p+ and 4e- . If we add
energy we can remove the electrons from the
highest energy level. The beryllium atom then
becomes a beryllium ion, which has 4p+ and
2e-. This means the ion has a charge of +2.
Be+2 is the symbol for the beryllium ion.
A sodium atom has 11p+ and 11e-. If the
electron in the highest energy level is
removed, a sodium ion remains. This ion
has 11p+ and 10e-, which means it has a
charge of +1.
Na+1 is the symbol for the sodium ion.
These ions are both cations (they have a positive charge).
An oxygen atom has 8p+ and 8e-.
Its highest energy level has 6 of a
possible 8 electrons.
O
When an oxygen atom gains 2
electrons from another atom’s
highest energy level, it becomes an
oxide ion.
This anion has 8 p+ and 10 e-. Its
symbol is O-2.
Electron Dot Diagrams
• Also called Lewis structures.
• Depict an element’s symbol with its valence
electrons
• ex.
Draw Lewis Structures for:
•
•
•
•
•
•
Hydrogen
Lithium
Calcium
Sulfur
Bromine
Neon
State the Protons, Electrons, &
Neutrons in the following
. Protons
200
80
Hg+1
53
24
Cr+2
75
33
As-3
Electrons
Neutrons .
An energy level gets filled when an
atom gains or loses electrons.
For example:
Na
Cl
[Na]+1 [Cl]-1
NaCl
Sodium (Na) needs to get rid of
one electron to have a full outer
energy level, and Chlorine(Cl)
needs to gain one in order to
have a full outer energy level.
Sodium chloride is formed when sodium
gives an electron to chlorine. Both atoms
become ions. This is called IONIC bonding.
another example:
Mg
O
Magnesium has two valence electrons.
Oxygen has 6 valence electrons.
Magnesium oxide is formed when
magnesium gives two electrons to oxygen.
Mg+2 O-2
MgO
Magnesium Oxide
What if:
Ca
F
F
Calcium has 2 valence electrons.
Fluorine has 7 valence electrons.
Calcium can provide 1 electron to fluorine.
What does calcium do with its other e-?
Ca+2 F-1 x 2
CaF2
calcium fluoride
Using Lewis structures predict the
ionic bonds that occur between:
1.
2.
3.
4.
5.
Potassium & bromine
Potassium & oxygen
Potassium & nitrogen
Calcium & chlorine
Beryllium & nitrogen
Draw the Lewis structures and
predict the formula for the following
ionic compounds. Name the ions
formed and draw their symbols.
a) magnesium & fluorine
b) lithium & bromine
c) rubidium & chlorine
d) calcium & oxygen
e) aluminum & oxygen