Chapter 5 Worksheet 1 – Key
1. State Heisenberg’s Uncertainty Principle as it pertains to atomic theory.
It is impossible to determine the exact location and momentum of a
moving object at the same time.
2. Why does the observation of a very small object such as an electron cause the
electron to have its motion changed?
The positions of very small objects like electrons can only be studied
accurately by hitting them with very high energy (x-rays, gamma
rays, etc.) and since the electron is so small it will have its momentum
(motion) changed to a large extent by this high energy wave.
3. What is wave particle duality?
Particles can sometimes behave as waves and waves can sometimes
behave as particles
4. What experiment supported the concept of wave particle duality?
The double – slit experiment.
5. What equation was able to calculate an electron behaving as both a particle and a
wave?
The Schrödinger equation (also known as the wave – mechanical
equation).
6. Describe the quantum mechanical (electron cloud) model of the atom.
The electron cloud is the three dimensional cloud of negative charge
around the nucleus of the atom that represents the space where the
electron is most likely to be found.
7. What scientist is most associated with the quantum mechanical (electron cloud)
model of the atom and the development of the quantum numbers?
Erwin Schrödinger
8. State a major difference between the Bohr Model of the atom and the quantum
mechanical model?
The Bohr Model model attempts to describe the path of each
electron in a fixed orbit. The electron cloud model describes the
possible positions of electrons in terms of “probability”.
Also the Bohr model of the atom is only able to accurately
describe electrons within a hydrogen atom whereas the quantum
mechanical is able to accurately describe larger atoms as well.
9. How is energy associated with the location of electrons within an atom?
Electrons have more energy the further they are from the nucleus.
10. Why is “probability” part of our current model of the atom?
This is because we can only make educated predictions as to the
“probable” location of the electrons.
11. What does the first quantum number tell us about an electron?
The distance from the nucleus (energy level) of the electron.
12. What does the second quantum number tell us about an electron?
The sublevel that the electron occupies.
13. Which sublevels are contained within the second energy level?
s and p
14. Which sublevels are contained within the fourth energy level?
s, p, d, f
15. What is an orbital?
An area of space in the electron cloud that can hold no more than two
electrons.
16. How many sublevels are in the 8th energy level?
8 sublevels
17. How many orbitals are in the 9th energy level? (9)2 = 81 orbitals
18. How many electrons does it take to fill the 10th energy level? 2(10)2 = 200
electrons
19. What is the shape of an “s” orbital? spherical
20. What is the shape of an “p” orbital? dumbbell
21. How many orbitals are in each type of sublevel (s, p, d, f)?
s = 1 orbital p = 3 orbitals d = 5 orbitals f = 7 orbitals
22. How many electrons does it take to fill a 4f sublevel? 14 electrons
23. How many electrons does it take to fill a 4f orbital? 2 electrons
24. What are the possible values of the fourth quantum number and what do these
numbers indicate?
+1/2 and -1/2. These values indicate the up and down spins of the
electrons within an orbital.