PERIODIC TABLE In 1869, a Russian Scientist, Dmitri Mendeleev created the very first PeriodicTable. He discovered a set of patterns that applied to all elements. To start, Mendeleev wrote each of the discovered 63 elements. He organizedthem based on their melting point, density, and color. He also included the element’satomic mass. Then he noticed a pattern and created the world’s first edition of whatwe know today as the Periodic Table of Elements. What is atomic mass? It is it the AVERAGE mass of all the isotopes of anelement. An isotope is an atom that has the same number of protons and adifferent number of neutrons of atoms of the same element.
HOW IS THE PERIODIC TABLE ARRANGED TODAY? Periodic=regular, repeated pattern Today’s table is arranged by atomic number Periods are found in horizontal rows. There are seven total on thetable. Groups are found in vertical rows. There are 18 families on thePeriodic Table. There are 117 known elements found on the periodic table. (althoughthere is no #117).
HOW IS THE PERIODICTABLE ARRANGED TODAY? The Alkali Metals are in Group #1 on the periodic table. Shadethem orange. They are very reactive and are always found incombination with other elements. The Alkaline Earth Metals are found in Group #2. Each is fairlyhard, gray-white and a good conductor of electricity. They are fairlyreactive although not as much as the Alkali Metals. Shade them inyellow.
HOW IS THE PERIODICTABLE ARRANGED TODAY? The Transition Metals are in groups #3-12. These include most ofthe familiar metals such as iron, copper, nickel, silver and gold. Mostare hard and shiny and are good conductors of electricity. Shade thesein green. In groups 13-15 on the Periodic table, only some elements aremetals. Most are not reactive—for example, aluminum, tin and lead.Shade the metals in the “mixed groups” in light blue.
THE PERIODIC TABLE TODAY The first row of elements that sit below the Periodic Table are calledthe Lanthanide series. They are located here to make the table morecompact. Lanthandes are soft, malleable and have a high conductivity.Shade the Lanthanides pink. The elements below the lanthanides are the actindes. Many of theactinides are not found naturally in nature but made in a laboratory. Someonly last a fraction of a second. These elements (man-made) are called“Synthetic elements.” Shade the actinide series red.
THE PERIODIC TABLE TODAY Non metals are elements that lack the properties of a metal. Mostnon metals are poor conductors of electricity and heat and arereactive with other elements. Solid non metals are dull and brittle. Ten of the sixteen nonmetals are a gas at room temperature. Someexamples are Oxygen & Nitrogen. Group #14 on the Periodic Table is the Carbon Family.
THE PERIODIC TABLE TODAY Group #15 is the Nitrogen family. It includes the elements Nitrogen,Phosphorus, Arsenic, Antimony and Brismuth. Group #16 is the Oxygen Family. Group #17 is the Halogens— “salt-forming.” These elementstypically gains are shares one electron when it shares with other elements. Group #18 are the Noble Gases. They are VERY unreactive andwere not discovered til the late 1800’s. Some examples include Helium,Neon and Radon.