1. Inert gases all have eight electrons in the outer energy level; they do not react; that is, they do not tend to gain or lose electrons Metals have one, two or three electrons in the outer energy level. Metals tend to lose electrons. Nonmetals have five, six or seven electrons in the outer energy level.Non-metals tend to gain electrons.

2. Octet rule: atoms become more stable (become less reactive, or get to a lower energy level) if they can achieve an electron configuration which has 8 electrons in the outer most level.

4. Formation of a positive ion
TV05A03

6. Formation of a negative ion
tv05A04

7. Formation of Magnesium ions: magnesium will lose 2 electrons; it will then have 12+ and 10-, making it a 2+ ion.
TV05A11animate

8. Both metals and nonmetals are “obeying” the octet rule when they transfer electrons because they end up with an outer energy level having eight electrons (there are many exceptions to these simple generalizations).

9. The reaction of chlorine with sodium

10. Ionic compounds are the result of a reaction which produces charged particles (ions)

11. Reaction of sodium with chlorine

12. When elements react to form an ionic compound, the result is a crystal in which positive ions are surrounded by negative ions and vice-versa. There is no individual molecule formed; only covalent com-pounds have molecules. The reaction will happen spontaneously (needs no energy input except the activation energy) because the elements are more stable (“happier”) afterwards.

22. Polyatomic ions = when groups of atoms, usually nonmetals, have a charge, and stay together in such a way to behave as if they were a single ion. Examples are carbonate, sulfate, nitrate, phosphate, hydroxide and ammonium.

24. Molecules are formed when atoms share electrons instead of transferring them; this occurs between nonmetals.