Name: _______________________________________ #: ____ Class: ____ Date: ____________________
QUIZ #5 – Atomic History and Structure EXTRA ASSIGNMENT
Atomic History
1. ORDER OF EVENTS: Using the numbers 1-5 (1 being the earliest), place the following atomic theories in
order, according to their development.
Atoms are made up of mostly empty space. Most of the mass is concentrated in the
center nucleus.
Negatively charged particles are called electrons. The atom is thought of as electrons
scattered inside a positively charged mass.
Electrons exist in a region around the nucleus called the electron cloud, where it is
impossible to predict the exact location of an electron.
Each type of matter is made up of only one type of atom. Atoms are tiny, indivisible
particles.
Electrons are arranged in particular energy levels. The atom resembled the solar
system.
2. Who first suggested the concept of atoms? ________________________
3. The “billiard ball” model was developed by ________________________
4. Which scientist discovered electrons? _____________________________
5. J.J. Thomson developed which model? ___________________________
6. Who performed the Gold Foil Experiment and discovered that atoms were mostly empty space?
___________________________________
7. Why is Rutherford’s model called the “Peach Model?” _________________________________________
8. Who came up with the “Planetary Model?” _________________________
9. In the “Planetary Model,” which part of the atom is the “sun”? _________________________________
10. What is today’s current model called? _____________________________
Atomic Structure
11. What is the charge of a proton? _______ Neutron? ______ Electron? ______
12. What particle(s) are found in the nucleus? ____________________ Energy levels? _________________
13. What does the atomic number represent? ____________________________
14. What does the mass number represent? ______________________ + _______________________
15. How would you determine the number of neutrons in an atom? ______________________________
16. How many electrons can each level hold? 1st = _____ 2nd = _____ 3rd = _____
17. What term is used for the electrons in the outermost shell or energy level? ____________________
18. Draw the Bohr Model for potassium on the back.