The Periodic Table By: Aditi Kamble and Saachi Katariya

Main Idea Scientists have identified more than 100 elements. Metals Semimetals Nonmetals The elements are organized in a periodic table.

Lesson Summary Dmitri Mendeleyev created the first periodic table He left blank spaces for elements that he believed would be discovered later Periodic Table: presents basic information for each element Elements are classified as nonmetals, semimetals, and metals Most metals are good conductors of heat and electricity

Vocabulary Chemical Symbol: An abbreviations of an element name Metal: A shiny substance that can be bent or stretched, and can conduct electricity Noble Gas: An element that hardly ever combines with another element to form a compound Non Metal: An element, usually in a form of gas, that cannot conduct electricity, does not stretch or are bend very much, and can break easily. Periodic Table: The table that logically arranges all known elements. Semimetal: an element that is like in some ways and like nonmetal in some ways.

Organizing the Elements Scientists have identified more than 1oo different kinds of elements Scientists have identified more than 1oo different kinds of elements Greek philosopher: Empedocles thought matter is made of 4 different kinds of elements Greek philosopher: Empedocles thought matter is made of 4 different kinds of elements fire, water, air, and earth fire, water, air, and earth Later, scientists identified more elements that fit in the periodic table Later, scientists identified more elements that fit in the periodic table

Mendeleyev’s Table In 1869, Dmitri Mendeleyev developed a way to arrange and classify the elements. Dmitri Listed the elements in order of increasing mass. Noticed a pattern repeating itself. He rearranged the list so that the elements with similar properties would appear in the same column. He predicted that in the future scientists would discover the elements that would fit in the blank spaces he left.

Mendeleyev's Table Cont. Today scientists use a table of elements similar to Mendeleyev's The periodic table is standardized Mendeleyev could not explain why should the pattern in the periodic table should exist Mendeleyev could not explain why should the pattern in the periodic table should exist

Mendeleyev's Table

The Periodic Table Elements are arranged by increasing atomic number Each box in the periodic table shows the atomic number, chemical symbol, and the name of the element Each column in the periodic table is called a group Each horizontal row is called period

The Periodic Table Cont. Elements can be classified as nonmetals, semimetals, and metals. Metal: bendable, conduct electricity, and can be stretched Nonmetals have properties that are the opposite of a metal Semimetals have nonmetal and metal characteristics Elements Bromine and Mercury are liquids, The symbols in red are gases and the ones in black are solids

Metals Metals include such familiar elements such as: iron, gold, nickel, silver, and aluminum. It also includes rarer metals such as: Technetium and Francium. One property that metal has is luster. They are not easily bent. They also conduct electricity. Most metallic objects are made from more than 1 metal.

Semimetals Semimetals: located between metals and nonmetals known as metalloids Semimetals: have the same properties like nonmetals and metals One example of a semimetal is silicon and 28% of earth crust is made from silicon Used to make electric circuits found in computer chips

Nonmetals Solid nonmetals are dull in color. Do not conduct electricity They are brittle Many nonmetals are gases

Noble Gases The last group of the periodic table is noble Gas Noble gas will glow if electric current passes through it. This makes neon Different gas mixtures make different colors.

Beyond The Book

Rare and Common Elements 99% of Earth is made of elements 8 elements make up Earth’s crust OxygenSiliconPotassiumAluminumIronSodiumCalciumMagnesium Elements combine to form compounds

Carbon Compounds There are nearly 10 million elements known as carbon compounds Important group of compounds: hydrocarbons. These are important fuels Carbon Compounds are the main parts of all living things Carbon Compounds fall into four main groups CarbohydratesProteinsLipids Nucleic Acids

POP QUIZ!!!!! 1.What is one element that makes up the Earth’s crust? A.Iron B.Banana C.Minions D.Donkeys 2. What is one property of a metal? A.Potatoes B.Milk C.Luster D.Mr.Ashraf

POP QUIZ #2 3. What are the 4 main groups of the carbon compounds? A.Pegasus, Donkey, Horse, Unicorn B.Carbohydrates, Proteins, Lipids, Nucleic Acids C.1,2,3,4 D ,200000,300000,

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