Periodic Table-History and Organization

element Triads have similar properties; quantitative properties of middle element are the average of the other two in the triad; had lots of exceptions

• Meyer

• Mosley

• Mendeleev

• Dobereiner

first to organize the elements by atomic mass; noticed patterns in every 8th element; law of octaves; left no gaps for future discovery; law of octaves did not work for larger elements

• Dobereiner

• Mendeleev

• Seaborg

• Newlands

synthesized many elements past Uranium and reorganized the table by adding an f-block

• Seaborg

• Mosley

• Meyer

• Mendeleev

organized elements by atomic number; modern periodic table; fixed some of inconsistencies from "best" of the historic periodic tables

• Meyer

• Mosley

• Newlands

• Mendeleev

organized elements by valence electrons; no gaps or predictions for unknown elements

• Mendeleev

• Dobereiner

• Meyer

• Mosley

Organized elements by atomic mass; related atomic mass to properties of elements; included all known elements at the time; left spaces and predicted where new elements would fit

• Newlands

• Mosley

• Meyer

• Mendeleev

Periods of the periodic table; mark all that are true

• rows

• columns

• always start with s orbital

• there are 7 periods

Groups of the periodic table; choose all that are true

• columns

• rows

• there are 8 main groups

• representative elements/A group elements

metals; select all that apply

• majority of elements

• shiny and conductors

• left side of PT

• most or gases

• malleable

Most reactive group with 7 valence electrons; exist as diatomic molecules; F is most reactive element in group

• Noble gases

• Halogens

• Alkali Metals

• Actinides