History of the Periodic Table

Greetings!

Today we shall be investigating the history of the periodic table!

Excuse me while I grab Micheal J. Foxx for our read today.

In the beginning

Chemists were starting to discover a lot of elements (62 by 1863).

They needed some kind of organization.

William Odling

• in 1857 separated known elements into 13 groups based on their physical and chemical properties

John Newlands

• in 1863 showed that by assigning Hydrogen an arbitrary mass of 1 and ordering known elements by masses, every 8th element shared comment set of properties. (Law of Octaves)
• this failed to predict elements and constantly changed the order the elements

Dimitri Mendeleev

Published method organizing the elements according to their masses and properties

• Showed elements listing according to masses and certain properties recurred periodically 
• broke list into series of rows/periods and columns/groups
• placed elements in certain groups based on properties in spite of contrary indications by its mass

He left gaps in his table, proposing that there where elements yet to be discovered

This allowed chemists to organize, understand data and predict new properties

Modern Periodic Table

Organized by atomic number rather than mass
Periodic Law summarizes the periodic table

• properties of the chemical elements recur periodically when the elements are arranged from lowest to highest atomic numbers

Major divisions of the periodic table are

• periods: set of all elements in a given row across the table
• groups/families: set of all elements in a given column going down the table

Chemical Families

• Metal and NonMetal Properties

• Metalloids
• or semiconductors are non-metals with electrical conductivity that increase with temperature
• have properties resembling metals more than non-metals
• the difference between metals and metalloids is
• metals conductivity decreases with increasing temperature
• metalloids conductivity increase with increasing temperature

Now that you are familiar with the periodic table, let us celebrate with a song!