Card Set Information
elements known since prehistoric times
industrial revolution, 1870 over ___ elements were known
found trios of elements with similar properties.
arranged elements by atomic weight and found that similar elements appeared to be 7 elements apart; "Law of Octaves"
pattern repeats in a specific manner
Organized elements, but no attempts at predictions.
-organized periodic table
-arranged in increasing atomic mass
-predicted existence of 3 missing elements; Sc, Ga, and Ge
determined atomic numbers of the known elements and rearranged the periodic table.
-put elements in order of atomic number not mass
the periodic table
the repetition of chemical and physical properties of elements when they arranged by increasing atomic number
elements with atomic number greater than 92 are ________
____ make up most of the elements of the periodic table
found in famalies 13-18
characteristics of both metals and non-metals
atoms in the same group have similar properties because..
same # of valence electrons
energy level of an elements valence electron indicates...
the period on the periodic table
valence electrons are the main source for..
-hold 2 electrons
-very active metals
-display a large range of chemical and physical properties
group 1, 1 valence electron