 This is half the distance between the nuclei of two identical atoms that are bonded together (distance from nucleus to outermost electron)  Trend increases as you move down a group/family and decreases moving to the right across a row

 Scientist who arranged the elements from lightest to heaviest and noticed that every 8 th element had similar chemical and physical properties

 This element is in the post transition metals, has 3 valence electrons, and an oxidation number of +3

 Created the first periodic table that was organized by atomic mass

 A semi-conductor that has properties of metals and nonmetals

 Characteristics include: dull, brittle, no conductivity, does not react with acid, and is on the right-hand side of the periodic table

 Family of the periodic table that is found in a free-state because it does not form compounds with other elements.  Oxidation number of 0, with 2 or 8 valence electrons

 This is an example of an alkaline earth metal

 States that properties of elements are periodic functions of their atomic number

 This is the energy required to remove an electron from a neutral atom  Increases moving to the right across a row and decreases moving down a group/family

 Family of the periodic table that has one valence electron and an oxidation number of +1  First column on left hand side

 Characteristics include: very good conductor, malleable, left-hand side of periodic table, reacts with acid, metallic luster, forms cations

 Scientist who grouped the elements into triads based upon similar properties

 Another name for this is series  It is what a row is called on the periodic table and it moves from left to right

 This is the most reactive and metallic metal on the periodic table  It also has the largest atomic radius

 This scientist was the first person to organize the periodic table by atomic number

 This is a halogen that has the greatest electronegativity, electron affinity, and ionization energy

 This is an example of a transition metal

 This is what the columns on the periodic table are called  Another name for this is family

 This is an example of an alkali metal

 This is an example of a noble gas

 This family of the periodic table has 7 valence electrons, an oxidation number of -1, and all three states of matter within the group

 This family of the periodic table has two valence electrons and an oxidation number of +2