The Periodic Table & Element Classes

The Periodic Table is the organization of known elements arranged by increasing atomic number (# of protons). This design was based on research by Henry Moseley (23 November 1887 – 10 August 1915)

The first periodic table was created by Dmitri Mendeleev a Russian chemist and inventor. Using the table he predicted the properties of elements yet to be discovered!

Group or Family Period

CA Standards Students know how to use the periodic table to identify alkali metals, alkaline earth metals, transition metals, metals, semimetals (metalloids), nonmetals, halogens and noble gases.

Metals

Properties of Metals Shiny—metallic luster Malleable—can be hammered or rolled into sheets Ductile—can be stretched into fine wires Tensile strength— resists breaking Most are solid at room temperature (except mercury) Good conductors of electricity and heat

Alkali Metals

Potassium, K reacts with water and must be stored in kerosene Alkali Metals NEVER found pure in nature because they are too reactive Reactivity of these elements increases down the group Group 1= Have 1 valence electron Potassium, K reacts with water and must be stored in kerosene

Alkaline Earth Metals

Alkaline Earth Metals less reactive than alkali metals not found pure in nature; they are too reactive The word “alkaline” means “basic” common bases include salts of the metals Ca(OH)2 Mg(OH)2 Group 2 = 2 valence electrons

Transition Metals

Transition Metals (still a metal just transitioning to non-metal) 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

Metaloides

Properties of Metalloids have properties of both metals and nonmetals. more brittle than metals, less brittle than most nonmetallic solids 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

Nonmetals

Nonmetals- 20% of elements Brittle Gases at room temperature (except: bromine= liquid, iodine, sulfur, selenium, phosphorus &carbon are all solid) Poor conductors of electricity and heat HYDROGEN is a nonmetal Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.

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

Halogens never found pure in nature; they are too reactive in their pure form are diatomic molecules (F2, Cl2, Br2, and I2) Group 7= 7 valence electrons Chlorine is a yellow-green poisonous gas

Noble Gases

Noble Gases They are ONLY found pure in nature – they are chemically unreactive!! Colorless, odorless and unreactive; they were among the last of the natural elements to be discovered Group 8 = 8 valence electrons (except helium, which has only 2)

Homework—Due Tuesday 9/20 Complete Periodic Table Activity Matter and Change Review Worksheet Chapter 1 Quiz

Periodic Table Coloring Get colored pencils from the back and open your book to pg 17. Color and label each section of the periodic table that we discussed today. Make a key at the top of your chart.