Chapter 5 The Periodic Law West Valley High School Chemistry Mr. Mata
Standard 1C How to use the Periodic Table to identify specific groups and trends for specific traits.
Essential Question How is the Periodic Table of Elements arranged to be a useful tool in chemistry?
5-1 History of the Periodic Table Cannizzaro (1826-1910) developed a method for measuring atomic masses. Stanislao Cannizzaro
Mendeleev (1834-1907) Created the 1st periodic table based on increasing atomic mass. Dmitri Mendeleev
Moseley (1887-1915) set up the periodic table according by increasing atomic number. Henry Moseley
Periodic = repeating pattern. Ex: days of week, months of year, seasons, ocean waves, life cycles. Periodic Table of Elements - refers to properties of elements that repeat on each row (period). Contains 7 periods.
Periodic law: chemical & physical properties of elements are periodic functions of atomic #’s. When elements are arranged in order of increasing atomic #, a periodic repetition of their properties occurs.
Periodic table: arrangement of elements in order of their atomic numbers. elements with similar properties are in the same family (group).
Group 1 (Alkali Metals) combine vigorously with many nonmetals. very reactive. not found in nature as free elements. Ex: Li, Na, K
Group 2 (Alkaline-Earth Metals) harder, denser, stronger, higher melting points than group 1. not found in nature as free elements. Ex: Mg, Ca, Sr
Groups 3-12 (Transition metals) Very colorful. Metallic properties. Copper Iron Groups 3-12 (Transition metals) Very colorful. Metallic properties. Chromium Cobalt
Most synthetically produced in labs. Cerium Lanthanides “rare earth” elements. Shiny, reactive, metals. Actinides Unstable; reactive. Most synthetically produced in labs.
Modern Periodic Table Glenn Seaborg (1912 – 1999). Discovered several transuranium elements. 1951 Nobel Prize in Chemistry. Element 106 (Sg) Seaborgium named in his honor.
Seaborg placed actinides below lanthanides These elements are sometimes placed beneath the rest of the table. Why???? …….to save space on table. allowed prediction of properties of newly-discovered actinides based on properties of lanthanides.
Let’s Compare! Nonmetals Solids, liquids & gases at RT Metals Solids are brittle and dull Poor conductors of heat & elect. Metalloids Properties of metals & nonmetals Mostly brittle solids Intermed. conductors of elect. - aka semi -conductors Metals Good conductors of heat & elect. Malleable Ductile Luster Solids at RT
Chapter 5 SUTW Prompt Describe the properties of metals, nonmetals, & metalloids and how they are arranged on the Periodic Table of Elements. Complete an 11-13 sentence paragraph using the SUTW paragraph format. Hilight using green, yellow, and pink. Due Date: Wednesday, October 5, 2016 (start of class).