Periodic Table
Developed by Dmitri Mendeleev Elements in order of increasing atomic #
Arrangement Metals on Left Properties of metals: ductile, shiny, malleable, conductive.
Arrangement Nonmetals on Right Properties of nonmetals: dull, brittle, insulators Sulfur
Arrangement Stair Step line of metalloids Metalloids are materials that share properties of both metals and nonmetals (ex. Brittle and shiny) Includes the elements B, Si, Ge, As, Sb, Te
Periods Horizontal rows Characteristics change as you move across the period Period # tells how many energy levels
Li
Groups/Families Vertical columns Elements in the same group have similar characteristics
Valence Electrons Valence electrons determine REACTIVITY with other elements They are involved in bonding. Groups 1-2 & 13-18: the ones place of the group # represents the # of valence electrons Ex. Group 1 has 1 Valence Electron Ex. Group 13 has 3 Valence Electrons Lewis Dot Structures show only the valence electrons around an atom.
Examples of Lewis Dot diagrams
Reactivity = Chemical Properties Valence electrons determine how likely an atom is to react with another atom Atoms want their valence orbital to be full 2 is considered full on first energy level 8 is considered full on 2 nd and 3 rd energy levels Atoms that have full valence shells do not react with other atoms.
Group 1 1 valence electron VERY Reactive Lithium, Sodium, Potassium, Rubidium, Cesium, Francium Shiny and soft enough to be cut with a knife, the alkali metals are usually white (though cesium is more of a yellowish white). When placed in a flame, most of these substances produce characteristic colors: lithium, for instance, glows bright red, and sodium an intense yellow.
Lithium Sodium
Group 2 2 valence electrons Less reactive than Group 1 They are silvery, shiny, and relatively soft metals
Group 3-12 Transition Metals Shiny, good conductors of heat & electricity Less reactive than groups 1 & 2 Includes the radioactive Lanthanides & Actinides
Group Includes Metals, Metalloids (B, Si, Ge, As, Sb, Te) & Nonmetals Same number of valence electrons as ones place of group #
Group 17 Halogens Most reactive nonmetals 7 valence electrons The term "halogen" means "salt-former" and compounds containing halogens are called "salts". The halogens exist, at room temperature, in all three states of matter: Solid - Iodine, Astatine Liquid - Bromine Gas - Fluorine, Chlorine
Group 18 Noble Gases Unreactive nonmetals – colorless, odorless gases Outer energy level is full Helium, Neon, Argon, Krypton, Xenon, Radon
Hydrogen Nonmetal that fits no other group It is often included above group 1 b/c it has 1 valence electron