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who was Dimitri Mendeleev?what did he create? |
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Definition
he was a russian chemist and a chemistry teacher: he created the periodic table. |
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how did he arrange his creation? |
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by increasing atomic mass in the same column. |
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where so a set properties repeat on the periodic table? |
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what value increases exactly by one from left to right across a row of the periodic table? |
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how is the arrangement of the modern periodic table that same as Mendeleev's? |
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each row in the periodic table is called a _______. |
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each column in the periodic table is called a __________. |
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what known as the pattern of repeating properties of elements |
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how is the atomic mass of an element determined? |
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Definition
weighted average of the masses of the masses of the elements isotopes. |
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what is used to define an atomic mass unit? what is the abbreviation? |
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how is an elements isotope used to find the atomic mass? |
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wighted average of the masses of the elements isotopes. |
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what are the 3 classes of elements? |
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Definition
metals nonmetals and metalloids. |
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give two characteristics of a metal. |
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Definition
not brittle, conductivity, solid at room temp. |
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describe two characteristics of a nonmetal. |
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Definition
brittle, low boiling point, poor conductivity. |
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what happens o nonmetals at room temp? |
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Definition
they turn to gases and brittle. |
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what is the most nonreactive nonmetal |
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Definition
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Definition
elements with properties that fall between those of metals and nonmetals. |
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across a period from left to right, how do the elements change? |
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Definition
become less metallic to more non metallic |
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what is a valence electron? |
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Definition
e- that is in the highest occupied energy level of an atom |
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elements in the same group have_______properties. why? |
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Definition
similar because they have the same number of valence electrons. |
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what are the elements in group 1a called? |
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how many valence electrons have to be extremely reactive? |
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to keep the valence electrons from reacting, what are they stored in? |
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where are the alkaline earth metals located? |
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what are these medals used for? |
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Definition
photosynthesis, chalk and coral |
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group 3a contains the _____ family |
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what is the most abundant METAL in earths crust? |
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in group 4a of the carbon family , what do most of the most compounds in your body contain? |
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most fertalizers contain what elements from group 5a... |
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___________is the most abundant ELEMENT in earths crust. the element that is found in nature only in compounds is SODIUM |
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how are halogens similar? |
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Definition
have the same chemical properties |
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the most reactive NONMETAL is also the halogen ______ in group 7a |
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which column contains the most reactive metals? |
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elements in group 8an are called the _____ ______ |
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list 3 characteristics of the noble gases. what can they be used for? |
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Definition
colorless, odorless, and extremely unreactive they can be used for neon lights |
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