1. Valence Electrons and Ions

2. Valence Electrons
Valence electrons are those electrons that have the highest energy level and are held loosely
The number of valence electrons in an atom help to determine properties of the element, including bonding properties
Each element has a specific number of valence electrons, ranging from 1-8; the number of valence electrons can be determined by the group/family the element is in

3. Alkali Metals (Group 1) have 1 valence electron; Alkaline Earth Metals (Group 2) have 2 valence electrons; Halogens (Group 17) have 7 valence electrons; Noble Gases (Group 18) have 8 valence electrons except for Helium and it has 2
Groups have 3,4,5, and 6 valence electrons respectively

5. Electron Dot Diagrams
An electron dot diagram includes the symbol for the element surrounded by dots; each dot stands for one valence electron

7. Ions An ion is an atom or group of atoms that has an electric charge
Atoms with 1-3 valence electrons usually become more stable by losing electrons
When an atom loses an electron, it becomes a positively charged ion
Positive ions are located in groups 1 and 2; there are some positive ions located in groups 3-12 as well as 13 and 14

8. Atoms with 5-7 valence electrons usually become more stable when increasing to 8
When an atom gains an electron, it becomes a negatively charged ion
Negatively charged ions are located in groups
Noble Gases already have 8 valence electrons, except Helium, which has 2, therefore, they do not form ions