Ionic Bonds

13.2

Ionic Bonds• Ions are atoms that have charges due to losing or

gaining electrons.• Ionic bonds form so that the outermost electron

shell is full• Ions that form are charged but the compound

formed from the bond is neutral because the opposite charges of the ions cancel each other out. Opposite charges hold the compound together.

• The attraction between opposite charges gives ionic compounds certain properties: brittleness, high melting points and high boiling points.

Forming Positive Ions• Atoms that lose electrons form ions that have fewer

electrons than protons, thus forming a positive charge.

• Atoms of most metals(left side of the periodic table) have few valence electrons tend to lose these electrons and form positive ions

• It takes energy to remove electrons from atoms.• The atoms in group 1 & 2 need so little energy to

lose electrons that they react very easily. Transition metals react but tend to hold on more tightly to their electrons.

Forming Negative Ions.• The outermost energy level of nonmetal atoms

(right side of periodic table) is almost full. Only a few electrons are needed to make a full shell so they tend to gain electrons to fill the vacancies.

• When atoms gain electrons, they have more electrons than protons, so they have a negative charge.

• The more easily an atom gains electrons the more energy the atom releases. Halogens give off the most energy when gaining an electron so they are the most reactive.