The Periodic Table of Elements

What is the Periodic Table of Elements?  The periodic table organizes elements in a particular way. A great deal of information can be obtained about an element due to its location on the table.  By looking at the location of an element on the table you can predict its physical and chemical properties.  The periodic table organizes elements in a particular way. A great deal of information can be obtained about an element due to its location on the table.  By looking at the location of an element on the table you can predict its physical and chemical properties.

Dimitri Mendeleev  He created the periodic table of elements.  He ordered the elements according to their atomic mass.  He created the periodic table of elements.  He ordered the elements according to their atomic mass.

Mendeleev’s Prediction  The periodic table of elements had missing elements or “gaps”.  Mendeleev was able to predict the characteristics of these missing elements.  The periodic table of elements had missing elements or “gaps”.  Mendeleev was able to predict the characteristics of these missing elements. Date Predicted1871Date Discovered1886 Atomic Mass72Atomic Mass72.6 Density5.5 g/cm 3 Density5.47 g/cm 3 Bonding Power4 4 ColorDark GrayColorGrayish White “Elkasilicon”Germanium

Henry Moseley  He revised the periodic table and arranged the elements according to their atomic number.

What is an element?  Elements alone or combined make up our bodies, our world, the sun, and even the entire universe.  Elements are natural or synthetic material that cannot be broken down into simpler materials by ordinary means.  An element has unique properties and is generally classified as a metal, metalloid, or non-metal.  Elements alone or combined make up our bodies, our world, the sun, and even the entire universe.  Elements are natural or synthetic material that cannot be broken down into simpler materials by ordinary means.  An element has unique properties and is generally classified as a metal, metalloid, or non-metal.

What’s in a square?  Each square on most periodic tables include the following:  Atomic number  Symbol  Atomic mass  Element name  State of matter at room temperature  Each square on most periodic tables include the following:  Atomic number  Symbol  Atomic mass  Element name  State of matter at room temperature

What’s in a square?  Atomic Number  This refers to how many protons there are  Atomic Mass  This refers to the weight of an element ( protons + neutrons) It is measured in AMU. This stands for atomic mass unit. 1 AMU= the mass of 1 proton  Symbol  Each element has its own unique symbol. It typically is represented by a capital letter or a capital letter and a lower case letter.  Atomic Number  This refers to how many protons there are  Atomic Mass  This refers to the weight of an element ( protons + neutrons) It is measured in AMU. This stands for atomic mass unit. 1 AMU= the mass of 1 proton  Symbol  Each element has its own unique symbol. It typically is represented by a capital letter or a capital letter and a lower case letter.

Common Elements and their Symbols SymbolElement OOxygen HHydrogen AgSilver NaSodium KPotassium

Metals, Non-Metals, Metalloids

Properties of Metals  Metals are:  Good conductors of heat and electricity  Shiny  Malleable  Ductile  A known chemical property of metal is its reaction with water which results in corrosion.  Metals are:  Good conductors of heat and electricity  Shiny  Malleable  Ductile  A known chemical property of metal is its reaction with water which results in corrosion.

Properties of Non-Metals  Non-Metals are:  Poor conductors of heat and electricity  They are NOT ductile or malleable  Solid non-metals are brittle and break off easily  They are dull  Most are gases  Non-Metals are:  Poor conductors of heat and electricity  They are NOT ductile or malleable  Solid non-metals are brittle and break off easily  They are dull  Most are gases Carbon

Properties of Metalloids  Metalloids:  Have properties of BOTH metals and non-metals  Are solids that can be shiny or dull  Can conduct heat better that non- metals, but not as well as metals  Are ductile and malleable  Metalloids:  Have properties of BOTH metals and non-metals  Are solids that can be shiny or dull  Can conduct heat better that non- metals, but not as well as metals  Are ductile and malleable

Families  Elements are grouped into families.  Families are vertical columns on the periodic table.  Each family has similar properties.  Elements are grouped into families.  Families are vertical columns on the periodic table.  Each family has similar properties.

Periods  Periods are horizontal rows on the periodic table.  Periods DO NOT share similar properties.  Periods are horizontal rows on the periodic table.  Periods DO NOT share similar properties.

Families & Periods Families  Columns in the periodic table.  Families share similar chemical properties, but are not identical.  For example, Li (Lithium), Na (Sodium), and K (Potassium) are all soft, shiny white metals.  All elements in a family have the same number of valence electrons. Periods  Horizontal rows in the periodic table.  They DO NOT have similar properties.  The first element in a period is an active solid and the last period is usually an inactive gas.

Why are elements important?  Almost everything in the universe is made of elements.  Hydrogen is an element. Oxygen is an element.  Elements can combine to make compounds or mixtures. H 2 o is 2 hydrogen and 1 oxygen.  H 2 o is water!  Almost everything in the universe is made of elements.  Hydrogen is an element. Oxygen is an element.  Elements can combine to make compounds or mixtures. H 2 o is 2 hydrogen and 1 oxygen.  H 2 o is water!