Bonding - Bonds and Electonegativity

There are 3 types of bonds. There is an ionic bond, which is the bond of a metal and a non metal. In ionic bonds, electrons are transferred from metal to non-metal. There is a covalent bond, which is the bond of a non metal and a non metal. In covalent bonds, electrons are shared between non metals. And there is a metallic bond, which is the bond of metals. A description of a metallic bond is: holds pure metal together by electrostatic attraction. 


After learning about bonds, we learned about electronegativity. Electronegativity (en) is a measure of an atoms attraction for electrons in a bond. For example:

• Flourine has an en. of 4.0
• Chlorine has an en. of 3.0
• Cesium has an en. of 0.9

You may be asking how we know the electronegativity of each. Well you can see by the table shown below:


Atoms with greater electronegativity attract electrons more. Polar covalent bonds form from an unequal sharing of electrons. Non-polar covalent bonds form from equal sharing of electrons.

We then went into more detail about bonds. The type of bond formed can be predicted by looking at the difference in electronegativity. For example:

• Electronegativity (en.) of the elements.
• en > 1.7 : ionic bond
• en < 1.7 : polar covalent bond
• en = 0 : non-polar covalent bond

Examples: Predict the type of bond formed

• O - O     3.44 - 3.44 = 0 non polar covalent bond
• F - Cl     3.99 - 3.18 = 0.81 polar covalent bond
• Ba - I     0.89 - 2.66 = 1.77 ionic bond