Atoms
• What is an atom?• http://learn.genetics.utah.edu/content/cells/s
cale/
• How did we discover the atom?• What do we already know about it?
History of the Atom
• Democritus• Dalton• JJ Thompson• Rutherford• Bohr• Other Scientists
Group Presentations
• 3 minutes to get with group
• Research the assigned scientist and their contribution to our knowledge of the atom
• Fill out the table about your scientist• Make a poster representing that information• 20 minutes – present to class
• Short Cartoon about History of Atom• TED Ed Talk on Size of the Atom
Thompson
• Veritasium: Thompson's Cathode Ray Experiment
Jan. 14 Warm Up
• In labbooks, answer the following questions:1. Who was the first to think of a particle so small it could
not be divided anymore? DEMOCRITUS2. Who discovered protons? RUTHERFORD3. Who used a glass tubing to find electrons? THOMPSON4. What does Bohr’s model most closely represent?
PLANETARY MODEL
So how far have we come?
Bohr Model – Model to describe atom
Arrangement of Atoms
• 100+ atoms, how do we organize them?• How could we organize them?
Interactive Periodic Tables
• http://www.rsc.org/periodic-table• http://www.ptable.com/
Reading Element Square
--------------------------------atomic number (Z); # of protons
--------------------------------atom symbol
--------------------------------atomic mass (# of P + # of N)
Atomic NumberAtomic number (Z) of an element is the number of protons in the nucleus of each atom of that element.
Element # of protons Atomic # (Z)
Carbon 6 6
Phosphorus 15 15
Gold 79 79
Mass Number
Mass number is the number of protons and neutrons in the nucleus of an isotope.
Mass # = p+ + n0
Drawing the Atom
Practice
• Which element has 4 protons?• Which element has a mass of 65 amu?• Which element has the symbol Ag?• Give an example of an element that has a full
energy shell• How many electrons does N have?• How many neutrons does Ca have?
Practice Drawing Atoms
• H• He• Li• Be• B• C
• N• O• F• Ne• Na