THE PERIODIC TABLE OF ELEMENTS An Introduction

The Periodic Table By 1850, approximately 60 elements are known Dmitri Mendeleev in 1869 publishes the first periodic table Lists the physical and chemical properties of the known elements Places elements with similar properties in families

First periodic table created by Dimitri Mendeleev in 1869.                                 

Mendeleev’s Periodic Table Published in 1871, St. Petersburg, Russia by Dmitrii I. Mendeleev

The Modern Periodic Table

CURRENT PERIODIC TABLE CONTAINS 113 ELEMENTS ORGANIZED INTO 7 PERIODS ORGANIZED INTO 18 FAMILIES/GROUPS

Why do we have those rows at the bottom? Tl Hg Au Hf Pt Ir Os Re W Ta He Rn At Po Bi Pb Cd Ag Zr Pd Rh Ru Tc Mo Nb Zn Cu Ti Ni Co Fe Mn Cr V In Xe I Te Sb Sn Ga Kr Br Se As Ge Al Ar Cl S P Si B Ne F O N C Li Be Na Mg K Ca Sc Rb Sr Y Cs Ba La Gd Cm Tb Bk Sm Pu Eu Am Nd U Pm Np Ce Th Pr Pa Yb No Lu Lr Er Fm Tm Md Dy Cf Ho Es Fr Ra Ac This arrangement takes too much space and is hard to read.

Atomic Symbols Each element is assigned a unique symbol. hydrogen H arsenic As uranium U radon Rn barium Ba gold Au titanium Ti potassium K Each symbol consists of 1 or 2 letters. The first is capitalized and the second is lower case.

The Periodic Table of the Elements Alkali Metals Alkali Earth Metals Halogens Nobel Gases Lanthanide Series Actinide Series Metals Non Metals Semi metals Representative Elements Transition Elements Periods Family or Groups

Metals, Semimetals & Non Metals H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe * Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn + Fr Ra Lr * La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb + Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No

Common group names Alkali metals Alkaline earth metals Halogens Noble gases I A II A III A IV A V A VI A VIIA 0 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar III B IVB V B VIB VIIB VIII B IB IIB K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Lr Gd Tb Sm Eu Nd Pm Ce Pr Yb La Er Tm Dy Ho Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No

The Elements in the Human Body Biochemistry Percent dry weight Carbon 62% Hydrogen 9.3% Oxygen 11% Nitrogen 5.7% Phosphorus 3.3% Sulfur 1.0% Calcium 5.0% Potassium 1.3% Sodium trace Chlorine trace Iron trace

THERE ARE 18 FAMILIES(GROUPS) PERIODS AND FAMILIES THERE ARE 18 FAMILIES(GROUPS) THERE ARE 7 PERIODS

EXTENDED FAMILY: METALS Have a high luster (are shiny) with most being silver/gray in color. Good conductors (carriers) of heat and electricity. Many have a high density Many are ductile (can be drawn into a wire form) Many are malleable (can be hammered into various shapes) High melting points. Majority of 113 elements are metals Most have 1-2 valence electrons. Metals hold onto electrons loosely—allows them to form metallic bonds.

METALS

FAMILY: ALKALI METALS (GROUP 1) MOST REACTIVE OF METAL FAMILIES Salt like in texture—can be cut with a knife Low density Good conductor of heat and electricity They can harm the skin They have 1 valence electron Most reactive metals Never found in the elemental form in nature. Always found as a compound with another element. They corrode very rapidly in air. Potassium and Sodium react very violently with water. They must be stored in kerosene or oil.

ALKALI METALS (Group 1)

Family: ALKALINE METALS EARTH METALS (GROUP 2) SECOND MOST REACTIVE OF METAL FAMILIES Harder and more dense than Alkali metals. Never found in the elemental form in nature, always found as a compound. Contain 2 valence electrons. They react very easily, but not as active as alkali metals. Have a higher melting point than alkali metals.

ALKALINE METALS (Group 2) Earth Metals

EXTENDED FAMILY: TRANSITION METALS GROUPS 3-12 Most commonly used metals in everyday life. Excellent conductors of heat and electricity High melting points High density Most are very hard, some are brittle Most have 2 valence electrons Much less reactive than alkali and alkaline metals. Many combine with oxygen to form oxides. Many can be found in elemental form in nature as well as in compound form (colorful-gold,silver) Iron,cobalt, nickel –can produce a magnetic field.

TRANSITION METALS (Groups 3-12) LANTHANOID SERIES ACTINOID SERIES

EXTENDED FAMILY: RARE EARTH ELEMENTS LANTHANOID SERIES Metals are soft and malleable. Have a high luster and conductivity Used to make various alloys (mixture of metals) and high quality glass Contain 2 valence electrons. ACTINOID SERIES After Uranium the rest are synthetic/man made in the lab. Contain 2 valence electrons Uranium=fuel for nuclear reactions

EXTENDED FAMILY: METALLOIDS Elements located along the dividing line between metals and non-metals. They have properties of both metals and non-metals. Metalloid means metal-like They conduct heat + electricity better than non-metals-but not as good as metals They are ductile and malleable. They are all solids that can be shiny or dull. Vary in valence electrons from 3 to 7. Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium, Astatine

METALLOIDS

EXTENDED FAMILY: NON-METALS Elements located to the right of the dividing line on the periodic table. Can be solid, liquid, or gas Physical and Chemical properties are opposite those of metals. No luster, dull Poor conductor of heat and electricity. Not ductile or malleable—Many are brittle. Lower densities + melting points than metals Contain 4-8 valence electrons Will share electrons—Not lose them. The positive nucleus will hold onto the electrons.

NONMETALS

FROM METALS TO NON-METALS Four families compose them. They have metals, non-metals, and metalloids. Families named after the first element in the group. Boron Family (Group 13)—3 valence electrons (all metals except Boron) Aluminum—outstanding metal Carbon Family (Group 14)——4 valence electrons—forms over 5million compounds. Carbon “basis of life compounds” Silicon—metalloid that makes glass, sand, computer chips Nitrogen Family (Group 15)——5 valence electrons—they will not give them up only share them. Nitrogen=70% of air. Phosphorus—nonmetal makes match tips. Oxygen Family (Group 16)——6 valence electrons—only share electrons

Carbon family Nitrogen family Oxygen family Boron family

FAMILY: HALOGENS MOST REACTIVE FAMILY OF THE NON-METALS Composed of 2 gases, 1 liquid + 2 solids Halogen comes from 2 Greek words Halos (salt) and Genos (to form) Contains 7 valence electrons Most active Non-metal family Will gain or share 1 valence electron When halogens react with metals they form salts Sodium fluoride-used to fluoridate toothpaste + water (prevent cavities) Calcium chloride—used to melt snow and ice Fluorine-most reactive element

HALOGENS (Group 17)

FAMILY: NOBLE GASES LEAST REACTIVE FAMILY ON PERIODIC TABLE All are gases and make up the last family. All are present in various amounts in atmosphere Used in colored lights (Neon=reddish orange) Helium balloons Called inert because they are not reactive Contain 8 valence electrons.

NOBEL GASES (Group 18)