Electronegativity

What is Electronegativity?
http://www.youtube.com/watch?v=93G_FqpGFGY


Why does Electronegativity Change for Different Elements?
http://www.youtube.com/watch?v=YZ8izzEq6zI

How does Electronegativity Affect Bonding?
http://www.youtube.com/watch?v=Kj3o0XvhVqQ