A foldable activity to help students learn historical development of the periodic table EXAMPLE

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2 A foldable activity to help students learn historical development of the periodic table Copies of each page should be made per student Each of the boxes below should be cut out Each of the two circles should be cut out and cut in half Fold each half in half to create four quarter circle flaps The front of flap should be the year or the span of years The boxes below will be glued into the inside appropriately dated quadrant EXAMPLE Completed and flaps closed Complete with one flap open

3 Antoine Lavoiser Listed the 23 known Relationships between atomic mass and elemental properties started being recognized Mendeleev gets credit because he published and explain it first More accurate methods of determining atomic mass were developed Boxes are arranged in increases atomic number to create columns (groups) and rows (periods) Non-metals are on the upper right side (above the stairstep) Electricity was used to separate more compounds to John Newlands first noticed repeating patterns in elemental properties every eight when in rows of eight Mendeleev organized by increasing atomic mass every eight element; this stacked with similar properties into groups Moseley corrected Mendeleev s table Total of seven periods Metalloids are found around the stair-step line Spectrometers were developed and used to identify Developed the Law of Octaves Blanks were left in the table where undiscovered should be located Moseley arranged by increasing number of protons Divided into representative and transition Modern By 1870s there were approximately 70 known Not accepted at first because of reference to music Predicted properties of undiscovered Table consist of boxes Three main types of : metals, non-metals, and metalloids 1790s- mid 1800s In 1860 chemist began using atomic masses to organize Meyer and Mendeleev both recognized a connection between atomic mass and elemental properties Some were out of order when arranged by mass Boxes contain atomic mass, atomic number, symbol, and element name Most of the are metals (largest left side portion) 1864

4 These are also cut and placed on the front of the appropriate quadrant with the dates

5 The Beginnings of the Periodic Table Before written history, people were aware of some of the in the periodic table. Elements such as gold (Au), silver (Ag), copper (Cu), lead (Pb), tin (Sn), and mercury (Hg). It wasn't until 1649, however, until the first element was discovered through scientific inquiry by Hennig Brand. That element was phosphorous (P). By 1869, 63 had been discovered. Creating Some Early Blocks for the Periodic Table Between , Johann Dobereiner began to group with similar properties in to groups of three or triads. This began in 1817 when he noticed that the atomic weights of strontium, Sr, was halfway between the weights of calcium and barium. These possessed similar chemical properties. By 1829, he had discovered the halogen triad made up of chlorine, bromine, and iodine and a alkali metal triad of lithium, sodium and potassium. He postulated that nature contained triads of in which the middle element had properties that were an average of the other two. Later, other scientists found other triads and recognized that could be grouped into set large than three. The poor accuracy of measurements such as that of atomic weights hindered grouping more Precursors to the Periodic Table In 1862, A.E.Beguyer de Chancourtois was the first person to make use of atomic weights to reveal that the were arranged according to their atomic weights with similar occurring at regular intervals. He drew the as a continuous spiral around a cylinder divided into 16 parts. A list of was wrapped around a cylinder so that several sets of similar lined up, creating the first geometric representation of the periodic law In 1863, John Newlands, an English chemist, proposed the Law of Octaves which stated that repeated their chemical properties every eighth element. The musical analogy was ridiculed at the time, but was found to be insightful after the work of Mendeleev and Meyer were published. The Fathers of the Periodic Table Lothar Meyer and Dmitri Ivanovich Mendeleev independently produced remarkably similar versions of the periodic table of at the essentially the same time. Meyer's 1864 textbook included a abbreviated version of a periodic table used to classify about half of the known. In 1868, Meyer constructed an extended table which he gave to a colleague for evaluation. This table unfortunately was not published until 1870, a year after Mendeleev's table was published. Mendeleev periodic table appeared in his work "On the Relationship of the Properties of the Elements to their Atomic Weights" in Mendeleev placed many out of order based on their accepted atomic weights at the time. Mendeleev predicted the existence and properties of unknown which he called eka-aluminum, eka-boron, and eka-silicon. The gallium, scandium and germanium were found later to fit his predictions quite well. The Modern Periodic Table Glenn Seaborg discovered the transuranium, atomic numbers 94 to 102. The completion of the actinide series allow Seaborg to redesign the periodic table into it current form. Both the lanthanide and actinide series of were placed under the rest of the periodic table. These technically should be placed between the alkaline earth metals and the transition metals, however, since this would make the periodic table too wide, they were placed below the rest of the. Dr. Seaborg and his colleagues are also responsible for the identification of more than 100 isotopes of.

6 Metals, Nonmetals, & Metalloids Most periodic tables contain a stair step line which allows you to identify which are metals, nonmetals, and metalloids. Following are descriptions of each of the three types of materials. Metals Most are metals. 88 to the left of the stair step line are metals or metal like. Physical Properties of Metals: Luster (shininess) Good conductors of heat and electricity High density (heavy for their size) High melting point Ductile (most metals can be drawn out into thin wires) Malleable (most metals can be hammered into thin sheets) Chemical Properties of Metals: Easily lose electrons Corrode easily. Corrosion is a gradual wearing away. (Example: silver tarnishing and iron rusting) Nonmetals Nonmetals are found to the right of the stair step line. Their characteristics are opposite those of metals. Since metals tend to lose electrons and nonmetals tend to gain electrons, metals and nonmetals like to form compounds with each other. These compounds are called ionic compounds. When two or more nonmetals bond with each other, they form a covalent compound. Metalloids Elements on both sides of the zigzag line have properties of both metals and nonmetals. These are called metalloids. Physical Properties of Metalloids: Solids Can be shiny or dull Ductile Malleable Conduct heat and electricity better than nonmetals but not as well as metals Information was obtained from various web sources. le.html Table/metals.html Physical Properties of Nonmetals: No luster (dull appearance) Poor conductor of heat and electricity Brittle (breaks easily) Not ductile Not malleable Low density Low melting point Chemical Properties of Nonmetals: Tend to gain electrons

7 Antoine Lavoiser Listed the 23 known Relationships between atomic mass and elemental properties started being recognized Mendeleev gets credit because he published and explain it first More accurate methods of determining atomic mass were developed Boxes are arranged in increases atomic number to create columns (groups) and rows (periods) Electricity was used to separate more compounds to John Newlands first noticed repeating patterns in elemental properties every eight when in rows of eight Mendeleev organized by increasing atomic mass every eight element; this stacked with similar properties into groups Moseley corrected Mendeleev s table Total of seven periods Spectrometers were developed and used to identify Developed the Law of Octaves Blanks were left in the table where undiscovered should be located Moseley arranged by increasing number of protons Divided into representative and transition By 1870s there were approximately 70 known Not accepted at first because of reference to music Predicted properties of undiscovered Table consist of boxes Three main types of : metals, non-metals, and metalloids Metalloids are found around 1790s- mid the stair-step line Modern 1800s Color Coded Key Non-metals are on the upper right side (above the stairstep) In 1860 chemist began using atomic masses to organize Meyer and Mendeleev both recognized a connection between atomic mass and elemental properties Some were out of order when arranged by mass Boxes contain atomic mass, atomic number, symbol, and element name Most of the are metals (largest left side portion) 1864

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