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31 Cards in this Set

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Periodicity
the grouping of elements by similar properties
Whoe discovered periodicity
Dmitri Mendelev
How did Mendelev arrange the periodic table?
in increasing atomic mass and found that you can build columns of similar properties
What did Mendelev postulate that gaps were?
Missing elements
What did Mendelev believe the irregularities were from?
errors in the atomic mass measurement
What did Henry Mosely find?
That each element has a unique nuclear charge and therefore a different atomic number
How did Mosely arrange the periodic table?
In order of increasing atomic number and the irregularities disappeared
What is periodic law?
the physical and chemical properties of the elements are periodic functions of their atomic number
Noble gases are also called...
inert gases because they are thought to be unreactive
What do xenon, krypton and radon have in common?
Low reactivity
Noble gas electron configurations....
have full s and p orbitals and r very stable
Alkali metals are (characteristics)...
soft and highly reactive metals
solid alkali metals are
good conductors of electricity
Alkali metals in gaseous state, at high voltages, make up for what?
electric currect flow by the motion of dislodged electrons
Characteristics of Alkaline earth Metals
harder, denser, stronger, and have higher melting pts than alkali metals
Alkaline Earth Metals are all..
reactive
Alkaline earth metals are not as reactive as alkali metals because...
they have to lose 2 electrons vs. the 1 electron of alkali metals in their outer shells
Lanthanides
shiny, metallic elements with atomic numbers 58-71 that fill the 4f orbitals
Actinides
metallic elements with the atomic numbers 90-103 that fill the 5f orbitals
Main block elements are also called...
the representative elements or transition elements
Main block elements include...
metals, non-metals, metalloids and noble gases
Halogens
combine easily with metals to form compounds like salts and are the most reactive non-metal
This element forms its own chemical family
hydrogen
Hydrogen is found in...
water, fats, proteins, carbohydrates and in fertilizers
Atomic Radius
increases as you move down through the elements in each group
Shielding effects cause the atomic radius
to increase because there is a reduction of the attractive force between a nucleus and its outer electrons due to the blocking effect of inner electrons
Atomic Size
decreases from left to right across a period
Ionization Energy
the energy you use to remove an electron
Ionization energy generally ______ as you move down a group of elements but ________ across a period
decreases, increases
Electronegativity
tendency of an atom to attract electrons to itself when it is chemically combined with another element
Electronegativity (decrease and increase)
Decreases within family, and increases within period