 In this video, we're going to discuss the octet rule and Lewis structures for simple just elements. If you recall from the periodic table, the noble gases, which are in group AA, are the least reactive elements on the periodic table. They are the least reactive because they have a full set of valence electrons. They have eight valence electrons. So all the other elements on the periodic table basically want to be like a noble gas and have eight valence electrons. And that's where the octet rule comes in. Atoms on the periodic table will gain, lose, or share valence electrons so that they achieve a full set of valence electrons, which is eight. Okay? However, there are a couple of exceptions to the octet rule. And those are hydrogen and helium. Since hydrogen and helium are on the first row of the periodic table, a full set of valence electrons consists of only two valence electrons. So hydrogen and helium will only have two. All the other elements on the periodic table will try to achieve eight valence electrons. We can represent the number of valence electrons in an element using Lewis symbols. We will use a dot to represent the number of valence electrons. Lithium only has one valence electron because it's in group 1A on the periodic table. Oxygen has four valence electrons. It's in group 4A, so that group number, when it's a representative element, tells you how many valence electrons it has. Oxygen's in group 6A has six valence electrons, so we have six dots around the symbol for oxygen. And neon is a noble gas. It has eight valence electrons, so we have eight dots around it, okay? Those are the Lewis symbols for just elements.