ChapterChapter 5

Types of Chemical Bond

IONIC BOND COVALENT BOND

ChapterChapter 5

Ionic Bonds

Metal Non-Metal

donate electron accept electron

ChapterChapter 5

ChapterChapter 5

In the formation of ionic bonds :

electrons are transferred from metal atoms to non-metal atoms.

metal atoms release valence electrons to form positive ions (cations).

Positive ions and negative ions are attracted to each other by strong electrostatic forces of attraction.

non-metal atoms receive electrons to form negative ions (anions).

ChapterChapter 5Sodium Chloride

A sodium atom with an electronic configuration 2.8.1 achieves stability when it releases one valence electron to form a sodium ion, Na+ an octet of electrons.

Na Na+ + e-

2.8.1 2.8

A chlorine atom with an electronic configuration 2.8.7 achieves stability when it accepts one electron from a sodium atom to form a chlorine ion, Cl- with an octet in its electronic configuration.

Cl + e- Cl-

2.8.7 2.8.8

ChapterChapter 5

ChapterChapter 5

Metal atoms will release their valence electrons to achieve the stable electron arrangement as in the inert gas.

Non-metal atoms will accept electrons in order to achieve the stable electron arrangement of the inert gas.

Ma XbNumber of electrons that will be received by X (or charge of X ion)

Number of electrons that will be released by M (or charge of M ion)

ChapterChapter 5

The total positive charge of the cation must be equal to the total negative charge of the anion in an ionic compound.

The formula of an ionic compound formed between them can also be derived as follows :

aMb+ + bXa- MaXb

Na+ + Cl- NaCl

ChapterChapter 5Example

1

Element M is an element from Group 13 and element X from Group 16 in the Periodic table. What is the formula of the compound formed between element M and element X ?

ChapterChapter 5

Solution 1

M from Group 13 has three valence electrons

and will form M3+ ion.

X from Group 16 will receive two electrons to

form X2- ion.

The formula of the compound is

M2X3

Charge of X ion

Charge of M ion

ChapterChapter 5

Group 15 ion, Z3-

Group 15 ion, Z3-

Group 15 ion, Z3-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

Group 16 ion, Y2-

Group 16 ion, Y2-

Group 16 ion, Y2-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

Group 17 ion, X-

Group 17 ion, X-

Group 17 ion, X-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

Formula of compound

AnionCation

ChapterChapter 5

M3Z

N3Z2

QZ

Group 15 ion, Z3-

Group 15 ion, Z3-

Group 15 ion, Z3-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

M2Y

NYQ2Y3

Group 16 ion, Y2-

Group 16 ion, Y2-

Group 16 ion, Y2-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

MXNX2

QX3

Group 17 ion, X-

Group 17 ion, X-

Group 17 ion, X-

Group 1 ion, M+

Group 2 ion, N2+

Group 13 ion, Q3+

Formula of compound

AnionCation

ChapterChapter 5

ChapterChapter 5