introduction to mendeleev’s periodic table of elements mrs. coyle
TRANSCRIPT
Introduction to Mendeleev’sPeriodic Table of Elements
Mrs. Coyle
“The Elements” Song by
Tom Lehrer
• http://www.privatehand.com/flash/elements.html
Organizing Information
• What criteria can be used?
• Activity “Organizing Cards”
How are days organized?
Dmitri Mendeleev
Russian
1860’s
The Person Who Organized the Elements
Mendeleev
• Teacher at St. Petersburg University.
• Was working on a textbook for his Chemistry students.
• He organized the 63 elements known at the time.
His Criteria
• Increasing atomic mass.
• Physical and Chemical Properties.
Sodium’s Reaction with H2O
Potassium’s Reaction with H2O
Periodicity
• Reoccurrence (repetition) of properties at regular intervals.
Mendeleev’s Periodic Table
Like A Calendar
Mendeleev’s Predictions
• He left spaces on the table for undiscovered elements.
• He predicted the properties of elements that had not yet been discovered.
• How?
Example: Eka-aluminum
• He placed this undiscovered element below aluminum.
• He predicted the melting point to be low and the density to be 5.9g/cm3.
• It was later found and named Gallium with a density of 5.91g/cm3 and melting point of 29.7oC.
Gallium
A brief comparison of the modern periodic table to Mendeleev’s
• What is the main criterion used to organize elements in the modern periodic table?
Recap
• Mendeleev’s Criteria
• Periodicity
• Prediction