Aim: How are Elements Organized in the Periodic Table? DO Now: 1. How would you organize these buttons? 2. How do you think elements are organized in the periodic table? 3. Write at least one trend you notice about the elements in the periodic table.

History of the Periodic Table The first periodic table was developed in Russia in 1869 by chemist Dmtri Mendeleev. He arranged elements in the periodic table in order of increasing atomic mass. The modern periodic law states: the properties of elements are periodic functions of their atomic number; elements are arranged in order of increasing atomic numbers. Chemists use the properties of elements to sort them into groups.

Periods and Groups Periods Horizontal rows of the tables The # of the period number indicates how many principal energy levels (shells) are in the element The number of valence electrons increases from right to left Properties of elements change across a period Groups or Families Vertical columns of the periodic table Most elements in a given group have the same number of valence electrons Elements of a given group have similar chemical properties

Classes of Elements 3 classes of Elements: Metals Alkali Metals Alkaline Earth Metals Transition Metals Inner Transition Metals Metalloids Nonmetals Halogen Noble Gases

Metals vs Non Metals General Properties of Metals solids at room temperature are malleable are ductile have luster good conductors of heat and electricity General Properties of Nonmetals many are gases at room temperature not malleable, tend to be brittle in the solid phase. surface is dull poor conductors of heat and electricity

Alkali Metals and Alkaline Earth Metal Alkali Metals Group 1 Most active metals in the periodic table All react vigorously with water to produce H 2 (g) They are shiny, have the consistency of clay, and are easily cut with a knife. Alkaline Earth Metals Group 2 Second most active metals

Transition Metals and Inner Transition Metals The elements in Groups 3 through 12 are called transition metals Typically hard solids with high melting points, with the exception of mercury

Metalloids Have properties similar to those of metals and nonmetals. They can be found adjacent to the stair-step line in the periodic table.

Halogens Group 17 Halogens have 7 valence electrons, which explains why they are the most active non-metals Halogen atoms only need to gain 1 electron to fill their outermost energy level. They react with alkali metals to form salts.

Noble Gases Group 18 Colorless gases Do not chemically react with other elements (inert) Are isolated atoms Are stable because their outer shells are full or have an octet

Activity Given the blank periodic table fill in each category with a different color. 1. Alkali Earth Metals 2. Alkaline Earth Metals 3. Transition Metals 4. Inner transition Metals 5. Metalloids 6. Nonmetals 7. Noble gases 8. Metalloids