The Periodic Table

Early Element Groupings

Group 1

Li, Na, K: Shiny, conductive, reactive

Group 2

Ca, Sr, Ba: Shiny, conductive, less

reactive

Halogens

F, Cl, Br, I: Similar properties

Development of the Periodic
Table

1

1869-1870

Mendeleev and Meyer arrange elements by atomic mass

2

1875-1886

Discovery of gallium and germanium supports Mendeleev's

work

3

20th Century

Periodic law based on atomic numbers established

Modern Periodic Table
Structure

1

Arrangement

Elements in order of increasing atomic number

2

Organization

7 periods (rows) and 18 groups (columns)

3

Element Information

Each box: atomic number, symbol, mass, name

Filling the Gaps

1

Prediction

Mendeleev and Moseley predict missing elements

2

Discovery

Tacke and Noddack find rhenium

3

Completion

Francium discovered by Perey in 1939

Element Classifications

Metals

Shiny, malleable, good conductors

Nonmetals

Dull, poor conductors

Metalloids

Moderate conductors, mixed properties

Element Groups

Main-group

Columns 1, 2, 13-18

Transition Metals

Columns 3-12

Inner Transition

Lanthanides and actinides

Specific Element Families

Alkali Metals

Group 1, form compounds with hydrogen

Alkaline Earth Metals

Group 2, form compounds with hydrogen

Halogens

Group 17, similar properties

Noble Gases

Group 18, inert gases