The Periodic Table By: Aditi Kamble and Saachi Katariya
Dec 22, 2015
Main IdeaScientists have identified more than 100 elements.
Metals
Semimetals
Nonmetals
The elements are organized in a periodic table.
Lesson SummaryDmitri 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
VocabularyChemical 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
Greek philosopher: Empedocles thought matter is made of 4 different kinds of elements
fire, water, air, and earth
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
The Periodic TableElements 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 stretchedNonmetals have properties that are the opposite of a metalSemimetals have nonmetal and metal characteristicsElements Bromine and Mercury are liquids, The symbols in red are gases and the ones in black are solids
MetalsMetals 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.
SemimetalsSemimetals: 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
NonmetalsSolid nonmetals are dull in color.
Do not conduct electricity
They are brittle
Many nonmetals are gases
Noble GasesThe 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.
Rare and Common Elements
99% of Earth is made of elements
8 elements make up Earth’s crustOxygen
Silicon
Potassium
Aluminum
Iron
Sodium
Calcium
Magnesium
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 groupsCarbohydrates
Proteins
Lipids
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 #23. 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. 100000,200000,300000,4000000