Bonding

[smk]

Hello:

 

How does an atom determine whether it will form a covalent bond or an ionic bond? Does electronegativity have anything to do with it?

 

Thanks for your help in advance!

[UC]

Hello:

 

How does an atom determine whether it will form a covalent bond or an ionic bond? Does electronegativity have anything to do with it?

 

Thanks for your help in advance!

 

Electronegativity has everything to do with it. As you may have guessed, covalent and ionic are not absolute terms. It is a range. The bigger the separation in electronegativities, the more polar they become, until the bonds become so polar that they can disassociate.

 

The general rule is metal + nonmetal = ionic, nonmetal + nonmetal = covalent, but this isn't always the case. If you look, I think you'll find that a Pb-C bond is less polar than the C-H bonds in hydrocarbons, which we often think of as the prime example of being nonpolar.

 

If you take metals to mean the alkali and alkaline earth metals, than yes, the rule applies.

Edited June 27, 2009 by UC