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Who was Lavoisier?
He grouped elements into categories in 1789: metals, nonmetals, gases, and earths
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What did Medeleev do in the 1860?
He developed a strategy for organizing the elements that was modeled after a version of the game of solitaire.
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periodic table
an arrangement of elements in columns, based on a set of properties that repeat from row to row
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Why did Mendeleev leave blank spots on the peirodic table?
He used the spaces in the periodic table to predict the differences of undiscovered elements.
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What is a period?
each row in the periodic table
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What was discovered before protons were discovered?
Mendeleev discovered the periodic table
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What predicted that Mendeleev's predictions were acurate?
The actual properties of the new elements
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What is a group?
each column on the periodic table
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What is the periodic law?
the pattern of repeating properties
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What is listed on the periodic table for each element?
the atomic number, the element name, element symbol, atomic mass #
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What is an atomic mass unit?
as 1/2 th emass of a carbon- 12 atom
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What is atomic mass?
a value that depends on the amount of an element's isotopes in nature and the masses of those isotopes.
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What are three ways to classify elements?
- 1. solids, liquids, or gases
- 2. occur naturally and those that don't occur in nature
- 3. based on general properties
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What are metals?
elements that are good conductors of electric current and heat
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What are nonmetals?
elements that are poor conductors of electricity
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What are transition metals?
elements that form a bridge between the elements on the left and right sides of the periodic table
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What are metalloids?
elements with properties between those of metals and nonmetals
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What is a valence electron?
An electron that is in the highest occupied energy level of an atom
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What are the Alkali metals?
- Lithium, Sodium, Potassium, Rubidium, Cesium, Francium
- Have a single valence electron
- are extremely reactive
- found in nature only in compounds
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What are Alkaline earth metals?
- Beryllium, Magnesium, Calcium, Strontium, Barium, Radium
- have two valence electrons
- harder than metals in Group 1A
- the differences are shown by how they react to water
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Describe magnesium.
- plays a key role in how plants use sunlight to produce sugar
- can be strong as steel but much lighter when mixed with other metals
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Describe calcium.
- keeps bones and teeth strong
- calcium carbonate is the main ingredient of chalk
- calcium sulfate is used to make casts
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What does the Boron family contain?
- Boron
- Aluminum
- Gallium
- Indium
- Thallium
- has 3 valence electrons
- Aluminum is the most abundant
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What is in the Carbon family?
- Carbon
- Silicon
- Germanium
- Tin
- Lead
- Have 4 valence electrons
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What is carbon?
- life on Earth would not exist without carbon
- Most compounds in your body contain carbon except water
- Carbon compounds control reactions that occur in the cells of your body
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What is silicon
the 2nd most abundant element in Earth's crust and is found in clay used to make pottery
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What is in the nitogen group?
- Nitrogen
- Phosphorus
- Arsenic
- Antimony
- Bismuth
- have 5 valence electrons
- the most important elements are nitrogen and phosphorus
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What is in the oxygen family?
- oxygen
- sulfur
- selenium
- tellurium
- polonium
- have 6 valence electrons
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Describe oxygen.
- the most abundant element in the earth's crust
- used to release the energy stored in food
- occurs in the form of ozone
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Describe sulfur.
main use is in the production of sulfuric acid, which is used to make fertilizer
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Describe sulfur.
main use is in the production of sulfuric acid, which is used to make fertilizer
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