Ionic Bonding

Atoms gain, loose, or share e- to become stable Octet Rule Atoms gain, loose, or share e- to become stable Want to have electron configurations like noble gases (8 valence electrons) Valence e- are found in the outer s and p sublevels

Ions Ion- atom or molecule that gained or lost e- becomes more stable. Cation- ion w/ positive charge (lost e-s) Usually metals Anion- ion w/ negative charge (gained e-s) Usually nonmetals

Nuclei of parent atom and it’s ion are same # of p+ and n0 are same. Parent atom and it’s ion have different: # e-s e- configurations chemical properties

Ionic Bonds Result from the attraction between cations and anions e- are transferred from one atom to another Creates a cation(+) and an anion(-) Many ionic compounds are called salts

Properties of Ionic Compounds Made from metals (cations) and nonmetals (anions) Strong bonds Hard Brittle High melting points High boiling points Solids are not conductors because the ions cannot move. Melts or dissolves, the ions can move about so are excellent electrical conductors

Salts A cation or anion attracts all of the oppositely changed ions around it Makes a tightly packed crystal structure Attractive force between oppositely charged ions is greater in a crystal than it would be if the ions existed only in pairs lattice energy = energy released when ionic bonds are formed Necessary to make the overall process spontaneous.

Making a Salt Releases energy (exothermic)

Unit Cell All salts are made of repeating units Smallest repeating structure is a unit cell Unit cells make the crystal lattice These repeating patterns make the crystal shape that can be seen in most salts.