Types of Bonds and Intermolecular Forces

Types of Chemical Bonds

What determines bond type?

• Elements all have inherent properties; one important property is electronegativity.
• Electronegativity can be thought of as "how much an element wants to hold on to electrons."
• Values for electronegativity can be found in the period table.
• When two elements combine to form a molecule, whether one atom steals the electron from the other, or whether the electrons are shared (almost) equally, depends on the electronegativity of each element.

• Electrons are shared between two atoms with similar electronegativities. Example: Water (H2O) results from the covalent bonding of 2 hydrogen (H) atoms to one oxygen (O) atom.
• They are more common and stronger than ionic bonds.

Ionic Bonds

• One element gains an electron and the other loses an electron to the other.
• Each element becomes an ion (charged). Example: Sodium chloride (table salt!) is made from the ionic bonding of sodium (Na) to chlorine (Cl). Because Cl is much more electronegative than Na, it steals one of its electrons. This causes both of the atoms to become ions (Na+ and Cl-), where the positive (+) charge indicates that Na has one less electron than it normally has, and the negative (-) charge indicates that Cl has one more electron than it normally has.