The Octet Rule
The octet rule states that an atom will gain or lose electrons to result in stability (a full or empty valence shell). Atoms are usually stable when they have 8e­ in their valence shell. Hydrogen and Helium are exceptions to this, as they are stable with 2e­ in their valence shell. (Recall the first ring can only hold 2e­)
The valence electrons are important in chemistry because these electrons are involved in bonding, which creates molecules/compounds/ions. Scientists have derived a method called ELECTRON DOT to show the arrangement of electrons around an atom. We will also (in the units to come) learn how to draw electron dot structures for Ionic and Covalent Compounds. Group 1A 2A 3A 4A 5A 6A 7A 8A # of valence electrons Example Electron Dot Diagram
Group Elements belonging to the d block Elements belonging to the f block # of valence electrons Example Electron Dot Diagram 1
UNIT REVIEW HANDED OUT TODAY.
KEY POSTED ON WIKI
2