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20 Cards in this Set
- Front
- Back
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What is the periodic table |
A chart of the elements arranged into rows and columns according to physical and chemical properties |
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Who created the periodic table? When? Why? |
Russian Chemist Dimitri Mendeleev
1869
Was working on a way to classify the elements |
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What are some example of physical properties that Mendeleev looked at to create his periodic table? Chemical properties? |
Observed density Color Melting point Atomic mass
How elements react to other elements |
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What kind of patterns did Mendeleev notice? What were the patterns of? |
Noticed periodic or repeating patterns
Patterns of elements melting and boiling point |
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When Mendeleev studied the table and discovered gaps, what did he do? What did Mendeleev believe about the nonexistent elements that we're to fill those spaces? |
Left gaps there because he predicted that scientists would fill in the gaps with elements they discovered
Believed these elements were to have similar properties to the elements near it
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Example of how Mendeleev changed his own table |
Placed tellurium before iodine despite it having a larger atomic mass because iodines properties more closely related chlorine and fluorine instead of tellurium (Elements were more closely related to their opposite neighbor) |
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How did Mendeleev originally have the periodic table organized |
From left to right with the Atomic mass Increasing by 1 |
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Who decided to rearrange the periodic Table? How did he do it and why |
Henry Moseley
Changed arrangement of atoms to a basis of atomic number instead of atomic mass
Found that if elements were listed according to increasing atomic number, columns would contain elements with similar properties
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How is today's periodic table organized? arranged ? |
In groups Periods And blocks (based on certain patterns of properties)
Arranged by increasing atomic number |
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What do on an element key? |
Element name Atomic number Symbol Atomic mass State of matter |
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What is a group
How are the elements in the same column related? |
A column on the periodic table
Same group have similar chemical properties and react with other elements in similar ways |
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How many groups are there? |
18 |
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What are periods
What happens to an elements atomic number as read from left to right across a period? What happens to the physical and chemical properties? |
Rows on a periodic table
Increases by one
Properties change as you move from left to right across a period ( follows patterns) |
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75% of the elements on the periodic table are what? |
Metals |
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Where are metals located on the periodic table? What are their properties? |
Found on left and middle of table
Properties: Shiny and conduct thermal and electrical energy |
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Where are nonmetals located? What are the properties of nonmetals on the periodic table? |
Right side of the table
Most are gases Poor conductors |
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What are Metalloids? Where are they located? |
In between metal/ nonmetals in both location on periodic table and properties |
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What are synthetic elements? |
Elements made by people in laboratories (don't occur naturally on earth)
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Why is the periodic table helpful? |
Helpful because it shows how elements relate to each other/ similarities in properties |
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Ex of How the periodic table can predict properties? |
Can predict properties of element 117 by looking at elements in the same group (would be very unstable because other elements in group 17 are also unstable) |
