The Periodic Table Table of Contents Lecture/Lab/Activity Date Pg# 14. The History of Atomic Models 9/14/ Structure of the Atom 9/15/ Isotopes9/16/ Beanium Lab 9/17/10 18.Electron Probability Lab 9/20/ Electron Configuration 9/21/ Orbital Diagrams9/22/ Electron Config Practice9/23/ The Periodic Table9/24/10 47 Objective: The student will review the historical development of the periodic table by creating a graphic organizer to compare how elements were arranged and their different properties. Agenda: The Periodic Table– Lecture

Mendeleev’s Periodic Table-1869 Dmitri Mendeleev Organized by increasing atomic mass Elements with similar properties are grouped together Predicted properties of undiscovered elements

Henry Mosely (1913, British) Organized elements according to atomic number Resolved discrepancies in Mendeleev’s arrangements

Periods and Groups Periods or Rows –Horizontal Rows –Numbered 1-7 –Indicate Energy Level (n) Groups or Families groups contain elements with similar properties in vertical columns. Group Numbers use the letter A for the representative elements (1A to 8A) and the letter B for the transition elements. also use numbers 1-18 to the columns from left to right

The Periodic Table Period Group or family Period Group or Family Roman Numeral = Valence electrons

Periods and Groups

Properties of Metals  Metals are good conductors of heat and electricity  Metals are malleable  Metals are ductile  Metals have high tensile strength  Metals have luster

Examples of Metals Potassium, K reacts with water and must be stored in kerosene Zinc, Zn, is more stable than potassium Copper, Cu, is a relatively soft metal, and a very good electrical conductor. Mercury, Hg, is the only metal that exists as a liquid at room temperature

Easily lose valence electron (Reducing agents) React violently with water Large hydration energy React with halogens to form salts Most Reactive Metal because of their readiness to form new substances Silvery solids with low density and low melting points The Properties of a Group I: the Alkali Metals

The Properties of a Group II: the Alkaline Earth Metals Alkaline earth metals are denser and harder and have a higher melting point than alkali metals in the same period Alkaline earth metals are reactive but not as reactive as the Alkali Metals

Properties of Nonmetals Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.  Nonmetals are poor conductors of heat and electricity  Nonmetals tend to be brittle  Many nonmetals are gases at room temperature

Examples of Nonmetals Sulfur, S, was once known as “brimstone” Microspheres of phosphorus, P, a reactive nonmetal Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

Group 17, Halogens Halogens means ‘salt- former’ Form Salts with Alkali Metal Group Reactivity: Fluorine (highest) and decreases going down group Iodine (lowest) F and Cl are gases Br is a liquid I is a solid

Group 18, Noble Gases Rarely react with other elements Low reactivity Have a full outer shell

Groups Group 13 – The Boron Family; all metals except Boron Group 14 – The Carbon Family; found in all living organisms Group 15 – The Nitrogen Family; health, environment Group 16 – The Oxygen Family; first two elements essential for life

Properties of Metalloids Metalloids straddle the border between metals and nonmetals on the periodic table.  They have properties of both metals and nonmetals.  Metalloids are more brittle than metals, less brittle than most nonmetallic solids  Metalloids are semiconductors of electricity  Some metalloids possess metallic luster

Silicon, Si – A Metalloid  Silicon has metallic luster  Silicon is brittle like a nonmetal  Silicon is a semiconductor of electricity Other metalloids include:  Boron, B  Germanium, Ge  Arsenic, As  Antimony, Sb  Tellurium, Te