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25 Cards in this Set
- Front
- Back
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Element
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A fundamental substance that cannot be broken down by chemical means to simpler substances.
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How many known elements are there?
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118
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T or F, all but the first 4 elements occur in nature
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T
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What is the smallest particle of an element that can exist?
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An atom
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What's the most abundant element in the earth's crust, oceans and atmosphere?
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Oxygen
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T or F, most elements are solid at room temp
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T
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How are elements arranged on the periodic table?
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in order of increasing atomic # (the # of protons found in the nucleus), e
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What are the 3 noble metals?
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Gold, Silver, Platinum
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Noble Gases are
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nonreactive
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3 different classifications of elements
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Metals
Nonmetals Metalloids |
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What are the 5 characteristics of metals?
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1. Lustrous
2. Malleable (able to be hammered into a different shape w/o breaking) 3. Conduct heat and electricity 4. Ductile (stretched into a wire) 5. High Density 6. High Melting point |
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What are the 6 properties of nonmetals?
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1. Dull (if solid)
2. (brittle (if solid) 3. Poor conductors of heat and electricity 4. Non-Ductile 5. Low density 6. Low melting point |
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Metalloids
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have properties that are intermediate between those of melts and those of nonmetals. Some are used to make the semiconductors we need for computer chips.
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T or F the noble gases are the least reactive elements and are found in uncombined form.
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T.
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List the 6 noble gases:
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helium
neon argon krypton xenon 86 radon |
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What elements are gases at room temp?
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The noble gases, nitrogen, oxygen, fluorine, and chlorine).
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What 2 elements are liquids at room temp?
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Mercury and bromine
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Diatomic molecules
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Each contain exactly 2 atoms. There are 7 diatomic elements. This is there stable form
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What are the 7 diatomic elements?
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Hydrogen
Nitrogen Oxygen Fluorine Chlorine Bromine Iodine |
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Compounds
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-Are composed of 2 or more elements combined in a difinite proportion by mass.
-elements are always combined in whole number ratios (AL2O3; KNO3) -can be decomposed chemically into simpler substances -Each compound has unique properties that are different from the elements that make it up. |
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What are the 2 different classifications of compounds?
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Molecular and Ionic
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Molecules
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-The smallest uncharged individual unit of a compound.
-Usually composed of two or more nonmetals. -Can be solids, liquids or gases. -Do not conduct electricity. |
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Water Molecules
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Can be decomposed into oxygen molecules and hydrogen molecules
The properties of water are very different from the properties of oxygen and hydrogen gas. |
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Ionic Compounds
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-Contain ions(charged particles).
-Compounds are held together by the attractive forces (positive ions) and the anions (negative ions) -Formulas are the simplest whole number ratio of each element. - Solids at room temperature -Conduct electricity when molten(liquid) (ex:NaCl) |
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Chemical formulas
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Specifies the number of atoms of each element in the compound. When the formula contains more than one of a group of atoms that occurs as a unit, parentheses are placed around the group and a subscript is placed to the right of the group.
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