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Golden Valley HS • Chemistry
Name _______________________________
Period: ______________
3 • Electrons & Periodicity
Models of the Atom – Notes & WS 1
Relevant textbook pages: 361 - 366
Section Objectives
 Students know protons and neutrons in the nucleus are held together by nuclear forces that overcome the
electromagnetic repulsion between the protons. (11a)
 Students know the nucleus of the atom is much smaller than the atom yet contains most of its mass. (1e)
 Students recognize the usefulness and limitations of models and theories as scientific representations of
reality. (I&E 1g)
 Students recognize the cumulative nature of scientific evidence. (I&E 1k)
Where we left off…
Rutherford (in 1911) discovered:
• atoms has a ____________________
• the nucleus is small, __________________________________________________________
• atoms are mostly _____________________________________________________________
2 years later…
Niels Bohr
• AKA ___________________________________________
• Proposed: e- arranged in _______________________________________________________
Bohr’s Planetary Model
First to answer the question:
e- in a particular path have a _____________________________________________________
No loss / gain of energy, _________________________________________________________
Energy level of an e-:
The region around the nucleus __________________________________________________
Fixed energy level of electrons
Similar to ____________________________________________________________________
Lowest energy level = lowest step
Higher the energy level, the farther ___________________________________________________
e- can change position or ____________________________________________________________
Quantum Mechanical Model
Erwin Schrodinger (1926) - Modern description of the atom
Based on statistical probability of the location __________________________________________
A.K.A. ________________________________
Dense area = ______________________________
• Quantum of energy is the amount of energy required to move an electron from its present
energy level _____________________________________________________________________
• Energy levels are made of ________________________, made of ________________________
S. Cool, 2009
1
• Energy levels are designated by principal quantum numbers (n); Range from: ______________
Energy Sublevels
•
•
•
Located within each _____________________________________________________________
Up to 4 sublevels: ________________________________
Maximum number of e- that occupy a level (n) = ____________________
Energy Sublevels
Principal Energy Level
Number of Sublevels
Types of sublevels
1
2
3
4
5
6
7
4
4
4
4
Sublevel
s
s
s
s
p
p
p
p
d
d
d
d
f
f
f
f
Atomic orbitals 2e- per orbitals
# of orbitals
Max # of electrons
s
p
d
f
1. Describe Rutherford’s model of the atom and compare it with the model proposed by his
student Niels Bohr.
2. What is an atomic orbital?
3. What is an energy level?
4. How many orbitals are in the following sublevels?
a. 3p sublevel ________
d. 3d sublevel ________
b. 2s sublevel ________
e. 4p sublevel ________
c. 4f sublevel ________
f. 1s sublevel ________
5. How many electrons can an orbital hold? _____________
6. How many electrons can be held in the first principal energy level? __________
7. How many electrons can be held in the third principal energy level? _________
8. How many electrons can be held in the fifth principal energy level? __________
9. What is the modern model of the atom called and who is responsible for its development?
S. Cool, 2009
2