ORGANIZING THE ELEMENTS Periodic Table

History 1700’s Lavoisier compiled a list of known elements Dobereiner published classification system. Grouped elements in threes Mendeleev arranged elements based on atomic mass. Meyer released a similar one a year later Moseley redid the table according to increasing atomic number

Periodic Table Periodic Law- when elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties Classes of Elements o Metals- good conductors of electricity and heat o Nonmetals- poor conductors of electricity and heat

Periodic Table o Metalloid- have properties of both metals and nonmetals Groups- vertical. Have similar properties. o Group 1 Alkali Metals. 1 vē, very reactive o Group 2 Alkaline Earth Metals. 2vē, less reactive o Group 3-12 Transitional Metals. 2vē, more common metals

Periodic Table Group 13, Boron Family, 3vē Group 14, Carbon Family, 4vē Group 15, Nitrogen Family, 5vē Group 16, Oxygen Family, 6vē Group 17, Halogens, 7 vē, very reactive with group 1 and 2 to usually forms salts Group 18, Noble Gases, 8 vē with the exemption of He. All very unreactive