Periodic Table Notes

The Periodic Table Notes
History of the Periodic Table * Two main contributors * Dmitri Mendeleev * Henry Moseley
Dmitri Mendeleev – Russian * 1869: published his periodic table with the 63 known elements * Arranged the first periodic table in order of increasing atomic masses
Henry Moseley – British * 1913 revised Mendeleev’s periodic table * Today’s periodic table * Arranged in order of increasing atomic numbers
What is the difference between Mendeleev’s table and Moseley’s? Mendeleev arranged his table by increasing atomic masses. Moseley arranged his table by increasing atomic numbers
Specific Areas and Their Properties * Alkali Metals – Group 1 Metals * Alkaline Earth Metals – Group 2 Metals * Transition Metals * Lanthanide Series – Rare Earth * Actinide Series – Rare Earth * Halogens – Group 17 * Noble Gases – Group 18
Families/Groups
* Vertical columns on the periodic table * Properties of elements are similar when moving down a group * Family 1: (Alkali Metals) * One valence electron (gives up this electron when bonding) * Very reactive with water and very soft * Burn if touched * Never found alone on nature * Stored in gasoline or kerosene * Family 2: (Alkaline Earth Metals) * Two valence electrons (usually gives up electrons when boding) * Slower to react than alkali * Found in earth’s crust and in minerals * Harder than group 1 elements * Family 3-12: (Transition Metals) * Number of valence electrons will vary * Next to last electron shell is filled after some electrons have gone into the last * Most familiar metals are transitions (iron, gold, silver) * Tantalum (Ta) is used in skull plates * Harder than alkali metals * Less reactive with water than alkali metals * Used for structure purposes * Titanium (Ti) is used on hip replacement * Harder and more brittle than group one or two * Have colorful compounds (used in fireworks) * Family 13: (Boron Family) * Three valence electrons * Includes Boron, a metalloid * Includes aluminum, the most common metal, in the earth’s outer layer * Family 14: (Carbon Family) * Four valence electrons * Will give electrons to another atom or take electrons from another when bonding * Family 15: (Nitrogen Family) * 5 valence electrons * Will take electrons from another atom when bonding * Family 16: (Chalcogen – ore forming) * Top two elements, oxygen and sulfur are commonly found in ores * Six valence electrons * Will take electrons when bonding * Family 17: (Halogens – salt forming) * Nonmetals * Iodine and bromine used in halogen lamps b/c allow tungsten filament to brighter w/o burning out quickly * Seven valence electrons – take when bonding * Rare in nature * Diatomic molecules – molecules that are made up of two atoms of the same element * Ex.: O2 * Family 18: (Noble Gases) * A.K.A. – INERT * ALL GASES * Eight valence electrons * Very stable; tend to not react with other elements b/c they have a full outer electron shell * Eight is a full electron shell in most cases
Why do atoms bond? * Atoms bond to achieve a stable octet * A stable octet is a full outer shell of electrons * For most a full shell is eight valence elctrons * Types of bonds * Convalent – electrons are shared b/w two nonmetal atoms * Ionic – electrons are transferred b/w a metal atom and a nonmetal atom
Lanthanide Series: (Sixth Period) * Begins with element 57, Lanthanum (La) * Elements in this series have similar physical and chemical properties * Usually found mixed together in the same locations in Earth * B/c properties are so similar the mixtures are difficult to separate, however recently they have been used in LED’s of laptops
Actinide Series: (7th Period) * Begin with element 89, Actinium (Ac) * Have similar properties, difficult to separate * Nuclear power industry uses Uranium and Plutonium * Actinides heavier than Uranium are synthesized in the lab, they are not found in nature
Lanthanide and Actinide Series * A.K.A. RARE EARTH ELEMENTS * Very radioactive
Regions and Their Properties * Metals * Shiny * Malleable * Malleable – hammered into thin sheets * Ductile * Ductile – drawn into thin wires * Good conductors * high melting and boiling points * usually solids * Tend to form positive ions when they bond * Nonmetals * Not shiny * Nonmalleable * Not dcutile * Poor conductors * Low melting and boiling points * Tend to form negative ions * Metalloids * Elements that aren’t metals or nonmetals but have properties of both