Valence Electrons and Ions

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

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 13-16 have 3,4,5, and 6 valence electrons respectively

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

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

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 15- 17 Noble Gases already have 8 valence electrons, except Helium, which has 2, therefore, they do not form ions