Ionic Bonding
Some atoms will interact to combine and from new substances. Atoms that interact in this way
are said to be chemically "__________". Whether atoms will interact to form chemical bonds
depends almost entirely on their _________ arrangement.
The electrons in the outer energy level can be called ________ electrons. It is these electrons that
determine the formation of chemical bonds. There are certain numbers of valance electrons that
are more stable than others. Atoms will ____ or ____ electrons in order to become more stable.
Atoms with eight valence electrons are the most stable.
To form Ionic bonds the electrons are ________________ between atoms.
•One atom ______ electrons while another atom _____ electrons.
•When this happens, the charges within each atom are no longer balanced.
•The atoms have become ions - one with a __________ charge, the other with a _______ charge.
•The force of attraction between these opposite charges holds the ions together in a/an _______
bond.
• The atoms of nonmetals generally (gain or lose) electrons in a chemical reaction.
• The atoms of metals generally (gain or lose) electrons in a chemical reaction.
The central idea of an ionic bond is that electrons (one or more, depending on the element) were
__________ between the outer rings (shells) of adjacent atoms.
The electron configuration for Na is 1s22s22p63s1. Sodium has three energy rings as shown by the
use of parenthesis 1s2)2s22p6)3s1 thus making the 3s1 electron the valence electron. The clearest
way to identify valence electrons is to use ________ _________
cores. Electrons in the outer shell are represented by dots representing electrons. For main-group
elements the number of valence electrons corresponds to the column that the element resides. The
orbital diagram is an excellent way to know how electrons are distributed that can be translated to
electron dot structures.
Note that the 6 electrons of oxygen are distributed as 2 pairs and 2 singlets.
Let X represent any element within a group and write the generalized electron dot structure for
each group.
IA
IIA
IIIA
IVA VA
VIA VIIA VIIIA
___
___
___
___
___
___
___
Write the electron dot structure for the following elements.
Al
K
Mg
Si
P
Ne
S
___
___
___
___
___
___
___
In general, metals lose electrons and nonmetals gain electrons.
___
Cl
___
Consider Na and Cl. Sodium would lose one electron and become positively charged and the
chlorine would gain one electron becoming negatively charged. The positive/negative charge
attraction would hold the two ions together.
1) In the above diagram the notice that Na1+ is called a cation and has no electrons around it.
Why?
2) Why is the chloride ion Cl1- is enclosed by brackets? What is communicated by the use of
brackets?
Na
atom
e 1-
Cl
atom
Na 1+
Cl
1-
Once atoms transfer electrons they become oppositely charged ions.
The anions become larger and the cations become smaller. Each cation is
surrounded by anions and vice versa. The ratio of Na to Cl
ions is 1:1 which matches Na losing 1 electron and Cl gains 1 electron.
3) In the above diagram how many units of NaCl can be counted? ____Sodium chloride, NaCl, is
not a molecule but is called a _______________unit. A crystal of an ionic compound consists of
a multitude of cations and anions yet the formula of an ionic compound can be reduced to the
_________ ratio, called a formula unit.
4) Draw a diagram showing how electrons are transferred between Mg and O.
The three ions would adhere (_______) to each other by the positive/negative attraction between
the ions. Ionic bonds occur between metals and non-metals on the periodic table.
5) Draw a diagram showing how electrons are transferred between Al and O.
Turn to your periodic table and examine the three columns headed by Li (ignore hydrogen, Group
IA or Group 1), Be (Group IIA or Group 2), and B (Group IIIA or Group 13). These columns
provide most (not all) of the positive partners involved in ionic bonding you will be held
responsible for.
The alkali metals) of column IA form ___________(charge) ions.
The alkaline earth metals) of column IIA form ___________(charge) ions.
In Group IIIA or Group 13 aluminum will form a + 3 ion, while the other metals can form +3
ions but some also form +1 ions.
Elements in Group VIIA or Group 17 will all gain one electron in ionic bonding and will
therefore be negative one.
Elements in Group VIA or Group 16 will gain ______ electron(s) to form _____charge. The
most common examples used from this column are O and S. Se and Te are used sparingly.
Polonium is a metal, and will not form a negative ion.
Finally, the column with N at the top and P just below will form a ____ ion. As and Sb are rarely
considered for ionic bonding and Bi not seen as a negative three.
When anions are formed their names change to end in -ide, but cation names do not change.
What is the name of the following elements when they exist as ions.
fluorine _____________oxygen _____________calcium _____________
bromine ____________ lithium _____________ aluminum _______________
Activity:
Add a full dropper of water and stir with the glass rod. Check the resultant mixture with
the conductivity device.
Use the conductivity device to learn if Mg ribbon will conduct electricity.
Place the ribbon into a crucible. Place the crucible into a clay triangle and cover the
crucible with the lid ajar. Heat the crucible for five minutes.
Turn off the heat. Use a glass rod and crush the product that has formed as the result of
burning magnesium with oxygen to form magnesium oxide. Check the white powder
with the conductivity device.
Allow the crucible to cool (about 3 minutes).
Table
Magnesium ribbon
MgO (white powder)
Powder plus water
Observation with conductivity device
Explain each observation:
Chemistry
Name____________________________
Below are the generic valence electron configurations for elements within a group.
A) ns2
C) ns2np1
E) ns2np3
G) ns2np6
B) ns2np5
D) ns2np2
F) ns2np4
H) ns1
1. List the three groups most likely to lose electrons?
2. List the two groups most likely to form anions?
3. Using the letter of the choice as a generic atom representing atoms for the entire
group, write the electron dot structure of each. (Example Choice A would be . A .).
B)
C)
D)
E)
F)
G)
4. Using the letter of the choice as a generic atom representing the entire group of
elements, write the formula of the ion that will be formed by each. Please note that this
does NOT involve dots.
A)
C)
E)
G)
B)
D)
F)
H)
5. Using the generic letters, write the dot structure of the ions formed by the following
groups.
A)
B)
E)
H)
6. Using the generic letters, write the dot formula for compounds involving the following
combinations.
A) B and H
B) A and E
C) H and F
D) F and A
7. Using generic letters write the empirical formula for compounds using the same
combinations as those used in number 6.
A) B and H
B) A and E
C) H and F
D) F and A
8. How do you interpret the following dot structure?